yes, the series 80 spring loaded thing to the aft of the slide.
I could not believe that brownells only had the colt part listed, and it was out of stock. Colt also said it was out of stock. When I asked the lady "if they did not have any, what were they putting in new guns?" she did not appreciate my snide remark, and said they "did not have any extras."
do you have any spares, or know where I might obtain one?