Yes the screw with flat head slot and jamb nut is a cam thing that limits regulator travel.
I dont know about the rubber bumper differences. My 67 has whats not much more than a piece of bicycle inner tube in it.
Thanks @RedFish , I didn't want to just start moving things without knowing.
As for the lower bracket, without any rubber on it the metal will 'almost' come up against the glass. I have some 1/4" closed cell neoprene I can glue on it. It appears it acts as a stabilizer of sorts when the window is down.
