My vintage Omega Seamaster with cal552 movement is coming up for a service (which I do myself). Last time I didn't replace the mainspring (it runs fine and keeps good time but the amp is a little low) and have since obtained a NOS genuine Omega replacement mainspring. When I remove/refit the mainspring is there a slipping part as the cal552 is an auto-wind? Is the slipping part integral with the new mainspring in the holding washer or does the old spring have a slipping part that needs to be re-used/replaced? Any help much appreciated.