When any FFL sells a lower rec of any brand taken off a rifle or not without an upper on it “other” is what should be on the 4473. This does not mean it may be legally assembled as a pistol. If the manufacturer has paid tax on it and listed it as a rifle that is what matters, most of the thousands of Colts are this. Only a very few the Brownells “SPARES” and a handful of Colt Commando can legally become pistols. All other Colts are rifles. When you purchase any Colt lower it is almost certainly a Rifle no matter what anyone said. The Brownells Spares have been verified by Colt not listed as a rifle so that is why only those lowers may become pistols, provided it is assembled as a pistol first. Even with the spares If you made it a rifle first it can never legally become a pistol. So if you are ever lucky enough to get one of these spares be sure to remove the stock and put an upper that has a bbl. length under 16” on it. Now it is legally a pistol and can be made into a rifle anytime you want-just be advised you must place the 16” or longer upper on it (or have no upper on it) before you slide the stock on. If you do not know the origin of your Colt lower you have to call Colt to verify it’s status. I do not know the exact number of spares-a couple hundred at best. And only released once. It is my opinion that even at $1k these are way undervalued. Out of thousands and thousands of Colts just a handful have this status making it one of the rarest ever produced. Collectors of Colts should definitely have one, but many do not understand this situation. I think I’ve explained it as best as possible PM me if you have questions.