I disagree with your second statement. TC won a court case years ago about contenders, people would take the pistol frame and put the carbine stock and barrel on, BATF said you could not go back to a pistol if you did that. TC sued and won, court ruled the original condition of the gun is all that maters. You can turn a pistol into a rifle and back to a pistol, but if it came from the factory as a rifle it is always a rifle. Uberti used to make a buntline with a detachable stock, with the stock off it's a pistol, on it's a rifle, go back and forth as much as you want.
http://www.gunbroker.com/item/607462200
That said I'm with Pat Riot, I'd only buy one from the factory.