Recently bought a Rolex 6239 which I'm in the process of restoring (got the case-back off).. It's marked inside as a 6239 - the watch's serial is in the 1.6 millions indicating mid 1960's (the case back is 6238 indicating earlier 60's when they used whatever hardware they had kicking around) but the piece sports an original 727 Valjoux movement which supposedly didn't show up until later 1960's 6262/6264's.
Also the dial sports the Daytona name top-center beneath cosmograph.. not arched over the subdial.. does anyone know when Rolex moved the Daytona name over the subdial?
The bezel indicates 300 units .. leading one to believe this is an early mid 60's Daytona, but the movement (which apears original and untampered) is too advanced for the case. Was Rolex experimenting with the 727 movement earlier in the 60's?