I believe that’s incorrect.
I do as well. Each 4473 contains the model and serial number of the firearm purchased as well as the identity of the purchaser. That information is retained at the FFL level for at least 20 years and may be called upon by subpoena, and is passed to the BATFE if that FFL holder goes out of business. And anyone who actually thinks that the FBI deletes it after completion of the NICS check as they are required by law to do thinks more of the integrity of that organization than I do.
They list the gun, the buyer and the serial number. By law they are supposed to destroy this NICS form if you pass the background check in 24 hrs. If you are denied essentially it goes into the FBI database the way I read the law.
The feds are supposedly prevented from creating a gun registration database, but since when has the ATF/FBI/DOJ obeyed any law?