Old thread but very, very good info. FYI--My slide stop spring (old-style) fell out during a mag catch spring change and it kept popping out just as I snapped the trigger guard into place. UGH! By the 4th try, I made sure it was flat against the frame and then put a dab (using a toothpick) of clear nail polish on the hook were it rested on the roll pin. All good now.