Mister green in the study with the lead pipe. sorry

That could very well be the answer... earlier Parker single selective trigger and subsequently a Miller trigger installed.

The L-S-R on the tang definately indicates an early Miller SST.
Chuck my Mom always told me "Son if your going to be an Ass, be a smart one as the world is full of dumb ones":rotf:

Yup, Parker trigger to Miller trigger to double triggers. Chuck, let me guess, you found this gun in Pennsylvania. I'll go one more. The stock has a pieced comb and a recoil pad installed with a hatchet.

Bill, sent you a PM