I am looking at this for 4,000 at a local pawnshop. He is trustworthy but not that smart. I worry it is a zombie. 1976 model on the ref. Number. I think the saphire and bracelet have been replaced.
More photos needed to help you- back, sides, bracelet markings, inside Caseback with reference number, and movement With serial number visible.
Is it working including chrono functions?
Service history?
The seller has it priced toward top end for this reference so need check it out further with above.
Dial and bezel look pretty good as a start.
The bracelet could be a significant part of the value, so we would need to see good photos of the clasp, blade engravings, endlinks etc. And don't take anything for granted if you think parts may have been put together.