Not sure but I think changes were made in 1964 so that barrels were interchangeable and that was also when they messed with the safety design. Mine was pre-64 and I swapped safeties with a guy who wanted a righty for his son and I wanted a lefty for one of my sons. Wouldn't fit.

There is a metal tab in the back of the trigger on the older ones which prevents the safety from the newer ones from fitting. Or at least that's what I think I remember...Geo

My older one fit his gun but his safety from the later (press checkered) gun did not fit mine.

post script: Woody, if you need a left handed safety from the newer model, I'll give you the one I have if I can remember how to take it out of the gun.

Last edited by Geo. Newbern; 07/07/18 08:17 PM. Reason: added final sentence