A PMF is a firearm, including a frame or receiver, completed, assembled, or otherwise produced by a person other than a licensed manufacturer, and without a serial number placed by a licensed manufacturer at the time the firearm was produced. The term shall not include a firearm identified and registered in the National Firearms Registration and Transfer Record pursuant to chapter 53, title 26, United States Code, or any firearm manufactured or made before October 22, 1968 (unless remanufactured after that date).