GMT 1675/16753 “Root-beer” - History Question

[thehunter]

I’m having a healthy debate with a friend on the history of the 1675/16753 RB. My RB is stamped with case-back 1675, and I understand dates to 1974. However I believe that by 1974 Rolex was using model number 16753 so I’m thinking my date is wrong. Does anyone know when the ref number change happened? I understood that 1675 RBs with applied logos from that era were quite rare - can anyone confirm that?

Also - I have seen some vintage stainless/gold RB’s that look to be ref 1675/16753 with a solid brown bezel - was this bezel factory issued on that model?

First picture is my watch - second one I took from the internet to illustrate the bezel I’m talking about.

Thanks everyone!