This might not be the right section but my question entails the handgunsi iv run accross so? But feel free to move it need it be......anyways......so over the past couple years iv been collecting s&w revolvers and iv bought a couple and when Iv removed the grips to clean them well I have run into 4 guns that have had a series of numbers in the format of xxx-xx-xxxx jst like a social security number pattern engraved into the frame of the butt they have no numerical connection to the serial number of the gun just a Random set of numbers in that pattern so im wondering was that the thing to do back in the day? doesn't seem smart nowadays .......also Keep in mind I have only seen this on s&w revolver.