Please explain where we "enter" serial numbers to get a hit. A 4473 does not include serial numbers, and I don't know any other place to enter the number.
'You' don't enter anything...into NCIC,,that is for L/E use only. Both entry, search, modify entry, retrieve, cancel, etc.
The system has enough errors in it with that.
The stolen gun info comes from a L/E stolen/lost firearms report.
The info gets into NCIC by that L/E agency then entering it into NCIC through their own computer terminal link.
Some small agencys didn't used to have their own terminal. So the Sheriffs Office or a Metro PD would enter their data for them using the smaller PD's identifier IRO.
The BATF only requires FFL's to report missing/stolen/lost firearms from their inventory to them.
But again the FFL must have the local L/E agencys report # (CR#) when reporting the incident to the BAFT.