Undetectable Firearms Act of 1988 - Amends the Federal criminal code to make it unlawful to manufacture, assemble, import, sell, ship, or deliver (or knowingly possess, transfer, or receive) any firearm which is not: (1) as detectable as the Minimum Security Standard Exemplar (after the removal of grips, stocks, and magazines) by walk-through metal detectors calibrated to detect the Exemplar; or (2) detectable by airport cabinet x-ray systems. States that nothing in this Act shall require the Federal Aviation Administration (FAA) to utilize the Minimum Security Standard Exemplar as an FAA detection standard.

Defines the term "Minimum Security Standard Exemplar" to mean a firearm substitute used for testing that resembles a revolver, is made of stainless steel, and weighs 3.7 ounces.

Prohibits the Secretary of the Treasury from authorizing the importation of undetectable firearms.

Directs the Administrator of the FAA to conduct research to improve the effectiveness of airport security metal detectors and airport security x-ray systems.

Allows the Secretary, when appropriate because of changed technology, to promulgate regulations to amend the definition of Minimum Security Standard Exemplar. Prohibits the Secretary from amending such definition so as to increase the weight of the Exemplar as set forth in this Act.

Permits the conditional importation of firearms for the purpose of examiniation and testing to determine whether the importation of such firearms will be allowed under this Act.

Directs the Attorney General, the Secretary, and the Secretary of Transportation to conduct studies to identify available equipment capable of detecting the Minimum Security Standard Exemplar while distinguishing innocuous metal objects.

Provides increased criminal penalties for using or carrying an undetectable firearm during the commission of a crime of violence or a drug trafficking crime.

Provides for the imposition of mandatory criminal penalties for using or carrying a firearm while assaulting a Federal officer.

Makes it unlawful to knowingly possess, or attempt to possess, a firearm or dangerous weapon in a Federal courthouse.

Makes it a Federal criminal offense to possess explosives in FAA regulated airports. Increases the criminal penalties for possessing explosives in Government buildings.

Increases the criminal penalties for using fire or explosives to commit, or carrying an explosive during the commission of, a Federal felony.

Prohibits the transfer of firearms to any person who does not reside in the State in which the transferor resides.

Makes it unlawful to traffic in stolen firearms (or firearms which have had their serial numbers altered) which have been shipped or transported in interstate or foreign commerce.

Makes it unlawful to manufacture, enter into commerce, ship, transfer, or receive any toy or imitation firearm which does not have markings which make it readily identifiable.

Undetectable Firearms Act of 1988 - Amends the Federal criminal code to make it unlawful to manufacture, assemble, import, sell, ship, or deliver (or knowingly possess, transfer, or receive) any firearm which is not: (1) as detectable as the Minimum Security Standard Exemplar (after the removal of grips, stocks, and magazines) by walk-through metal detectors calibrated to detect the Exemplar; or (2) detectable by airport cabinet x-ray systems. States that nothing in this Act shall require the Federal Aviation Administration (FAA) to utilize the Minimum Security Standard Exemplar as an FAA detection standard.

Defines the term "Minimum Security Standard Exemplar" to mean a firearm substitute used for testing that resembles a revolver, is made of stainless steel, and weighs 3.7 ounces.

Prohibits the Secretary of the Treasury (Secretary) from authorizing the importation of undetectable firearms.

Directs the Administrator of the FAA to conduct research to improve the effectiveness of airport security metal detectors and airport security x-ray systems.

Allows the Secretary, when appropriate because of changed technology, to promulgate regulations to amend the definition of Minimum Security Standard Exemplar. Prohibits the Secretary from amending such definition so as to increase the weight of the Exemplar as set forth in this Act.

Permits the conditional importation of firearms for the purpose of examiniation and testing to determine whether the importation of such firearms will be allowed under this Act.

Directs the Attorney General, the Secretary, and the Secretary of Transportation to conduct studies to identify available equipment capable of detecting the Minimum Security Standard Exemplar while distinguishing innocuous metal objects.

Provides increased criminal penalties for using or carrying an undetectable firearm during the commission of a crime of violence or a drug trafficking crime.

Provides for the imposition of mandatory criminal penalties for using or carrying a firearm while assaulting a Federal officer.

Makes it unlawful to knowingly possess, or attempt to possess, a firearm or dangerous weapon in a Federal courthouse.

Permits the court to consider pretrial detention for certain firearms and explosives offenses.

Makes it a Federal criminal offense to possess explosives in FAA regulated airports. Increases the criminal penalties for possessing explosives in Government buildings.

Increases the criminal penalties for using fire or explosives to commit, or carrying an explosive during the commission of, a Federal felony.

Prohibits the transfer of firearms to any person who does not reside in the State in which the transferor resides.

Makes it unlawful to traffic in stolen firearms (or firearms which have had their serial numbers altered) which have been shipped or transported in interstate or foreign commerce.

Firearms Detection Act of 1988 - Amends the Federal criminal code to make it unlawful for any person to manufacture, assemble, import, sell, possess, receive, ship, or deliver any firearm which is not: (1) as detectable as the Minimum Standard Security Exemplar, after removal of grips, stocks, and magazines, by walk-through metal detectors commonly used at U.S. airports; or (2) impregnated with barium sulfate, or a similar compound, to facilitate detectability by cabinet x-ray systems. Defines the term "Minimum Security Standard Exemplar" to mean a firearm substitute used for testing that resembles a revolver, is made of stainless steel, and weighs four ounces.

States that nothing in this Act shall require the Federal Aviation Administration (FAA) to utilize the Minimum Security Standard Exemplar as an FAA detection standard.

Prohibits the Secretary of the Treasury from authorizing the importation of undetectable firearms.

Directs the Administrator of the FAA to conduct research to improve the effectiveness of airport security metal detectors and airport security x-ray systems.

Allows the Secretary, when appropriate because of changed technology, to submit proposed legislation to amend the definition of Minimum Security Standard Exemplar.

Directs the Administrator of the FAA, the Director of the Secret Service, and the Director of the Marshals Service to conduct a study to identify available equipment capable of detecting the Minimum Security Standard Exemplar while distinguishing innocuous metal objects.

Provides increased criminal penalties for using or carrying an undetectable firearm during the commission of a crime of violence or a drug trafficking crime.