That means when they run the serial numbers, the pistol is effectively then registered in a govt. database.
Hence the reason the #'s was entered...
Consiracy theories aside, I do beleive in this day and current terrorist environment your son and wife acted correctly. The campus cop Was overzealous in reaching through the window as he was probably never rebuffed by students (absolut power corrupts...) and by the time the deputy gets there consent to run the numbers has already been implied.