The story of the Rolex Oyster Cosmograph (with screw-down waterproof pushers) started in 1965 with the launch of ref. 6240. In 1971, the ref. 6263 (with acriclic bezel) and 6265 (with steel bezel) were introduced to replace the previous models: they had a larger winder, a solid bracelet and were both powered by Rolex cal. 727 (based on Valjoux 72).
Here are some close-up pictures of my former ref. 6263 Cosmograph from 1974. The watch was special in the sense that the dial had white gold markers (hence the sigma-T-swiss-T-sigma at the bottom) and did not have the Daytona mention on it, like on ref. 6240.
The dial was really nice for a 30 years old watch, the subdials were rather "dark grey" than really black:
Here you see the engravings of the reference and serial number between the lugs:
The flat caseback and the solid bracelet ref. 78350:
A view of the cal. 727 and the inside caseback (no mention of the reference here):
A side view of the screw-down waterproof pushers and the relatively large winding crown:
A picture in the appropriate context...
Finally some documents to illustrate the vintage Cosmographs: