The above watch is one of my mostly omega collection, but recently found that the rotating bezel had fallen off and luckily I found all the parts so am able to repair, I think..
Pardon my ignorance, but as a precision engineer, what looks like a bottom lock ring has a fracture (see photo) and as I see it the ring should be one piece which is pressed onto the body and the flat spring and castellated bezel sits on top and held in place with the four very small retaining screws.

I am hoping some one on this forum can tell me this is correct so I can send the watch off for a service and replacement ring.