Good evening, guys. Approximately what year did Smith & Wesson start offering the 1/2" wide target trigger on the K-frame models, like the 14 and 15 (or Pre-14 and Pre-15, whichever the case may be)?

I have the chance to buy a 1952 Pre model 14, which has a target hammer, but no target trigger. It just has the standard width (.265"?) serrated trigger.

Thanks for the help!
Phillip