This question is going to be asked A LOT in the coming months with the expiration of the 50oz limit on pistols.
It makes NO difference what your dealer marks on the 4473 or how the receiver is marked. All that has already been done before the receiver is "disposed into commerce" aka sold by the manufacturer.
As soon as a serial number is applied to a receiver, the manufacturer has to report it to the ATF. He reports it as a pistol, shotgun, rifle etc. There is a sub-category in this report that reflects whether or not it is "Barreled". In other words, when you buy a new stripped AR receiver, the ATF already knows that it left the factory without a barrel aka a complete firearm. Manufacturers are very careful to get this right as there are excise tax ramifications.
The only thing I would worry about is buying an already built pistol or "stripped" receiver from a private party. Even if they tell you it has never been built into a rifle you never really know. If, in such a case, the serial number was reported as a "Barreled" rifle to the ATF, you are screwed.