Hi Pete, you're touching on a very common topic with this... what do we do when the supply of NOS genuine parts runs out?
I've got a 6536/1 Submariner from 1958 and spent many years sourcing the pieces to put it back to as-new condition (plus a lot of accumulated wear). My original bezel was so worn, there was NO lip remaining to hold an insert. I started the search and finally found a genuine NOS bezel, and paid dearly for it... and discovered the hard way that it fit the 6538, with a different diameter. I sold it on (someone got a screaming deal) and kept looking for a genuine 6536/1 part. I have yet to find one. But I did find several aftermarket bezels that ranged from terrible to pretty darn good. So I kept the best one, an extremely generous friend sent me a vintage fat fonts insert, and voila' the Sub was reborn. To my eye it looks exactly like the genuine piece, so I'm happy.
Now the question: what will the boys on TRF and VRF say when their vintage bezels pop off (they are soft metal and they do get loose) and they're unable to find a replacement? Now, they look down their long nose and sniff at "replica" watches that have one aftermarket part. What will their song be when their favorite vintage piece loses its bezel? Will it become an unwearable paperweight, or will they follow the path I did? At what price are we willing to accept that good aftermarket parts are just as good as genuine?
And so here we are at good old RWG. We're willing to accept gens, frankens and nasty cheap $100 replicas. In the end these are just wrist watches. It's the meaning our hearts give them, that make them valuable.
Do some searching for threads by freddy333 and cc33 about bezels. They've posted some high def photos showing the pieces available from different suppliers. Suppliers and factories do change though, so you may be starting from scratch. You also might try contacting Mary, she has her own parts subforum here. She is amazing... tell her exactly what you want and chances are she can find one for you. Be kind and gentle with her, she's a treasure.
Good luck!