Different thickness bezel 60’s vs 80’s Speedmaster

Goodmorning everybody!

I have a question. I looked in my Moonwatch only book and searched on the internet but cannot find anything about it..

The edge of the bezel of my 68-er Speedmaster is a lot thicker then the edge of my 86-er Speedmaster.

If I look on the internet i see also some 60’s Speedmaster with the Sharp bracelet. Are these replaced?

Has the thickness of the gezel changed when they introduced the DNN bezel or has 70’s Speedmasters still the thick bracelet ?

Who can tell me more about it ? Thank you !

I know, sorry I did not mention...

It makes it only stranger.....because then we can say there are 2 types of 70's/80's bezels.... one with a thick edge and with a sharp edge..??