I have a 4" S&W no dash 624. These things are on the butt. Can anyone explain such??

I have always understood those are assembly numbers and the 'touchmarks' of various inspectors and/or assemblers.

Neat though....I've never seen the heart.

Mostly, they're assembly and inspection numbers. The only marking I know of other than the standard serial numbers, is a when there is a star stamped (I believe) on the butt of the frame indicating it has been back to the factory at some point in time for refinishing, or other issues.

Murphy

Thanks guys. Pretty much what I figured. I did find the double S & heart strange.