Related to this, if your gun has an arrowhead stamped on the frame, it means the gun passed through the armorer's school. I have a Model 65, 3" RB which I purchased while attending the school and mine does indeed have the arrow. However, the gun was stock, without any customized details.

The armorer's school was a good place to buy guns because both a student and an S&W armorer went over the gun to insure it was mechanically perfect.