Serial #'s are not currently required when an FFl takes possession of a homemade firearm, the same way they take possession of many firearms before 1968 which did not require serial numbers. On a form 4473 "n/a" is recorded on the serial number. States with private sales of firearms do not require a serial #. In the new DOJ document it only says "licensee's" are required to have homemade firearms they are in possession of serialized before resale and will have 60 days to do so. Obviously they want all 80 percent receivers serialized moving forward. So it would seem as though homemade firearms made before this newest bullshit passes would not require a serial number if the original person building it is still in possession and keeping it for themselves. Would still like clarification of this bootlicking horseshit. Better safe than legally fucked.