I recently bought a used Mod. 60 which had these grips on it. They look like they are from the Fuzzy Farrant "school" of grip making, but don't look enough like what he's done for me to be able to tell.
There is palm swell on the left side with the checkering. The right panel is flat and smooth. Which makes me think it was more for a left handed shooter. OR a righty that didn't like clothes or jacket grabbing on the grip. There are no markings anywhere.
So I'll post some pics and see what you guys think.