I am not quite sure which piece you are talking about , do you mean the piece that fits onto the joint pin with a screw if so its called a cam . This prevents the barrels form over opening and also cocks the ejectors . There are a few floating around but may take some time to find one . It will also need to be correctly fitted to limit the gape as well as its cocking function .
As I recall there were a lot if not all 720's and 728's sent out in green canvas and leather Brady cases . I had the job of putting the case labels in and fitting the stop blocks for the stock heel.
