This Rudy has a couple of notable features and has been pretty heavily used. First off is the wire ball detent, something I am always happy to have compared to the ball bearing style. a little below it is a hole, this was to adjust a set screw on the hammer that locked the hammer lug in place. Although a good idea, it never became popular. The internals are all AKA, but the grip frame was supposedly replaced sometime ago by a previous owner with a hinge. I have since swapped in a benchmark slider.