George,
Take your combination gun to Pat Felix in Cusseta GA.(just outside Ft. Benning).A reflex sight is light enough that an unobtrusive base can be screwed to the rear section of the top rib. If you don't like it, the base can be removed and the screw holes filled to match the "matting" on the rib. I don't recall if you ever said where you live, but you must be within driving range of Cusseta.
Mike