[Alpo]

I'm pretty sure they don't care so much about the ownership of the parts, as they do about the proximity of the parts.

If you own a gun, and I own the conversion parts, and you're in Kaintuck and I'm in Florida, they don't care, but if we're both in the same apartment, then there's a machine gun in that apartment.

If you, for example, are a convicted felon, and they catch you with a gun, tellin' 'em, "It ain't my gun, it's Alpo's" won't help. You will still get arrested. I think it's the same thought process.