...I know this subject has been bounced around here enough, but I'm trying to settle an issue for a guy before he jumps into a pool of sh!t. While at a gun show, he purchased a 'preban' BM lower from an FFL. Supposedly, the FFL stripped the lower from an assembled rifle he had for sale at his table. OK, now the guy buys a 'preban' after market upper from a different party to complete the rifle. I'm not really clear on just how 'stripped' the lower was at the time of purchase. I know it was purchased with a collapsible stock, so I'm assuming all the lower guts were intact. It allegedly was new/unfired. The bottom line is, should there be any concern about mating these two components, thus creating the dreaded 'manufacture of an Assault Weapon' scenario?

If it has a true preban serial number don't worry about it. That having been said, I've seen many an postban AR sold as "preban" at gunshows.

as long as the serial number is right i wouldn't worry about it.  i would definately make sure it's in the right # range though.

The correct answer is that it SHOULD have had the pistol grip AND a collapsible stock attached to the receiver at the time of purchase to be considered a "grandfathered assault weapon".

Then again, I doubt anyone would care.

If all goes well his and my Preban will both be NORMAL when the AWban grandfathers and both will be near worthless.  

I will then replace my out-of spec lower with a new lower that is current spec and has the reinforcements where they should be.  

Some say (like an ATF agent did in an opinion letter) that its only preban if its never sold stripped. How are they to prove it was not sold complete?