These are 3 pictures of my lettered pre-war RS. I agree that your gun is an R. If it were MY R and I tried to pass it off an an RS I would have tried to find these studs
NRA Endowment Life Member (and proud of it)
Nowadays people know the price of everything and the value of nothing.
Wise men speak because they have something to say; fools because they have to say something. - Plato