It's my understanding, IIRC, while building up 80% lowers is legal, transfering/selling the lower from the "builder" to a third party, the lower should have some type of serial number on it prior to the transfer or sellin of said lower.
Interesting aside:
I have a 80% lower, which I built well before the AWB, (like mid 1982). This lower has no makings at all and my delima is that I was unaware that I needed to document when I built the lower, (only found out about this after I began posting/reading here). Hence I am now the owner of self-built "pre-ban" lower receiver, with no markings and no way to prove I built it prior to the AWB, save except for some reciepts for the lower parts kit and stock, which probably is NOT good enough for the alphabet boys...
This is somewhat of a bummer, any suggestions?
Mike