With all the brace drama, I should clarify this post.
As a complete lower that has never had a barreled upper, this is still a legal receiver. It is neither considered a pistol, nor a rifle.
As an 01 FFL, I am also not allowed to reconfigure it. I can't add a barrel and make it a rifle. If it comes onto my logbook as a receiver, it must leave that way.
I don't expect anyone to buy it, if a dealer wants to sell something the last thing they would do is post it on GCGF, but there is not any legal reason to remove it either. It's just a receiver, and an odd curio at this point.