Just found a bag of parts. 1911 colt 22 conversion unit 22 long rifle. It contains: 2 clips, slide, spring, barrell, arm that holds slide and frame together and flat bar that locks into side of barrell. Missing is the piece that goes over spring and the lock on the end of the barrell. Is there anything else missing? Can i put this all together and put it on my old 1911 45 remington made in 1943? Probably a stupid question, but i am a rookie! Also in the bag was a colt mk iv model 80 slide, spring, barrell and barrell lock. Will these interchange? Thanks