Yes, it is.
However, though it is not the same as registration, it could be used to populate a registration, but would probably be wildly inaccurate because it does not track what happens to the gun after it leaves the store. If the police come to your door, you can just say you sold it. The government does not actually get those forms until a dealer closes up shop (though theoretically the could com in an copy them all). The government does like to collect information and we are all probably on several lists anyway, but so far they have better things to do than going to the trouble to go to the dealers and copy these forms.