My old service revolver, (which was given to me when I retired)
Is that a Model 19?
I have a 19-3 that looks just like that gun that was a police trade-in and is marked "W.P.D" followed by the number "142" (both visible above trigger). It even has the same grips as the one in your pic. I'm thinking about sending it to S&W to get reblued.
Here's a pic of mine: