...sigh...
i suppose its my fault for not specifying what i consider the obvious when buying a stripped lower receiver.
this is a BRAND NEW lower receiver, FROM THE FACTORY. i SERIOUSLY doubt they assembled it, test fired it with no upper, stripped it, then sent it out.
this thing has obvious sanding/milling done to polish up the receiver after it was molded. my guess is that one of the machines had an "oops", or maybe it broke when the lower was removed from the molding.
bottom line, im not concerned with what it looks like or how it happened. im only concerned with - is it structurally sound?