The Original Red Field Scopes were made in Denver Colorado. Just north of E. Evans & S. Holly St.
The E.P.A. made them go out of business many years ago.
I have a Red Field 4x my dad bought me back in the early sixties. We went to the factory & purchased it. You could also buy Blems. I have it on a 30-06, Model 70, 30-06 Winchester, made in 1946. Still have it.
I wouldn't get to paranoid about the found rifle. If it doesn't work it's nat a real firearm. If you could find a ser.# that would be cool to find the owner.
Good luck.