Again, I just recall something along those lines when people were discussing Pre & post ban rifles WRT the '94 ban and federal law.
IIRC, basically the BATFE ruled that since its a receiver, not a rifle until its assembled, it had to be assembled before the ban went into affect. Again, the '94 federal AWB has expired so that portion is moot, a person needs to get into the specific state law.
How would they prove it? I don't know, maybe by your weapon having all new production post ban type evil features. Sure you could say you swapped them all out from older production preban stuff... But then you'd be lying...
Again, no dog in this fight as I don't intend to move to a Kommunist state.

