I am far, far from an expert on vintage Rolex, in fact the brand is usually of minimal interest to me.  But I do enjoy following guys who get around the vintage Rolex world such as Philipp of Rolex Passion Report (the vintage Rolex Man, and also behind the Rolex Hillary-Tenzing Explorer Series) and more recently Boris of Watchesandart who blogs about general vintage including Rolex.  Boris recently shared an excellent look at a Rolex Daytona Reference 6263 from 1970s with rare Sigma dial (white gold indexes) –  get more details on the piece at Watchesandart blog.  A beautiful watch.

Rolex Daytona Reference 6263 Sigma Dial

 circa 1970s