The Correct Chronology of the Watch
In order to correct the previously invalid chronology of the watches, it was necessary to seek independent verification of what the watches looked like at the production stage.
With this particular model given the rate of attrition, and the more than average frequency of swapping of movements, dials, bezels and even cases it became vitally important to reference independent, reliable documentation. A cursory examination of Seamaster 600s that were photographed and went for service at Omega Bienne shows that over 60% have suffered a movement swap.
So for the purposes of confirmation, the Author has included internal documentation held in the Omega archives detailing the watches original built specification and subsequent configurations.

Omega archives
Original registered design patent for the MARK 1 watch, 1st edition retail.

Omega archives
Omega archives: Press release issued in February 1971 announcing the arrival of the MARK 1 1st edition watch shown on the isofrane strap with the red plastic lock nut.

First catalogue
One of the first printed catalogues specific for the US market dated February 1971 showing the watch to be available for order and delivery from April 1971. Note this is the MARK 1 watch, 2nd edition with the steel replacement lock nut.

Omega archive documentation
Production specification for the MARK 1, 1st edition watch isofrane strap, red plastic lock nut, but indicating the option for a 1162/162 steel bracelet

Omega archive’s internal documentation
MARK 1 watch 2nd edition, showing the transition to a steel lock nut

Omega archive’s internal documentation
MARK 3 watch showing the D3 dial, B2 bezel now on the mesh bracelet onwards from 1975

MARK 3 watch showing the range of optional metal bracelets
Because of a lack of rigorous research in this model, the important connections between the Seamaster 600 (Ploprof 0) and the Seamaster 1000 (Ploprof 1) have been ignored. In 1972 both watches were available with identical dials, identical hands, identical bezel designs and identical calibre movements. The Seamaster 1000 of this period is extremely rare and for more information collectors should refer to www.omegaseamaster1000.com.
The History
In the late 1960s underwater exploration, off-shore oil constructions and maintenance, as well as applications such as scuba diving, water sports, and sub-aqua military and naval special forces, saw an increase in demand for underwater watches.
The number of employees of underwater contractors at the time exceeded 3000 of which a 1500 were commercial divers.
So the demand for a robust, waterproof, legible, reliable and high-depth rated watch caused the development by Omega of the unmistakable Seamaster 600 debuting at the 1969 Basel Show and being issued for retail sale in April 1971.

Pre-production prototype identical to the 1st issue but with a dial zero.
Despite it being a superb professional divers watch it also had a big following in the retail market.
Gianni Agnelli, the chairman of Ferrari and Fiat and one of the most prominent public figures in Italy had an allergy to the metals used in watch cases.
This led him to wear his Seamaster 600 on the outside of his cuff and this idiosyncratic display enhanced the watches visibility and hugely boosted demand.

Gianni Agnelli wearing the Proplof