For a seller CYA, I’d be surprised if people are not at least completing a bill of sale. A FTF transaction of a serialized lower without an FA10 doesn’t somehow obliterate the chain of ownership.
No. And frankly, if I were still in MA, I’d never EFA10 a built firearm again after the FRB doxxed everyone. Registration is supposed to be illegal and is unconsitutional. Registration is the step right before confiscation.
What Toast said. If it was sold as a serialized lower, it came from an FFL. If we needed FA10s to trace guns, the ATF wouldn’t be able to trace any gun outside MA.