Just like good evidence handling practice, consider marking your OWN guns in a less than obvious spot with your initials and something like date of birth. Unless your name is "Steve Watson" or "Sam Wellington"..
Also, if the gun has serial numbers, frame numbers, cyl numbers, other markings that differ, record them all. If it's ever stolen, when it gets entered into NCIC as a stolen gun, it might not be the ser# that they enter or that gets run later when found. If you are able to report all the various numbers, and your OAN (Owner Applied Number - could be letters and/or numbers) and all those numbers are entered, it's more likely to get a hit if run later. Zat make sense? Say your gun's stolen today and they enter your serial number (only) as stolen. A year from now, a beat cop runs the frame number (different from the ser#). If that frame number wasn't entered initially, the gun won't return as stolen.
Those of you who you think every LEO in the universe is out to get you and steal your guns, feel free to disregard the above suggestions.