I believe the CD is a series 70 gun. you can tell by removing the slide and looking at the bottom of it. I f there is a small plunger that must be pushed up to release the firing pin you have a series 80 gun. I ahve a 1991 colt compact (series 80 type) and love it but am not wild about the idea of extra parts that could cause problems. Just like my win model 94 with a safety on it. Too many lawyers.