So playing devil's advocate does this mean that if I own a T/C registered as a pistol and another registered as a rifle that I would not be allowed to own another (3rd) barrel?
I've read the post from the BATF (a copy of their letter was in the post) on another forum that said until you attach the barrel to the weapon you have NOT crossed their lines. If I remember correctly it was on a T/C forum. With that information I would argue that there is a government agency that has done the interpretation of the the law. I am not sure how it would hold water so YMMV.
If this was not the case I think a lot of T/C owners would be in a lot of trouble.