The Road Rat - A Chronomaster Glimpsed?

Issue 11 of The Road Rat includes a feature on '50s/'60s U.S. racing driver, Walt Hansgen.  The article include the photograph of Walt seen below.  Author Colin Goodwin suggests that the watch Walt is wearing is a Tudor, but it looks to me like a Nivada Grenchen Chronomaster Aviator Sea Diver. Wonder if anyone here can confirm please?

Further Diver's Data Sheet Update - two Depthomatics

 

Updated Data Sheet for Divers

 

Some interesting detail points of dial difference between DBND013 and 012.  At the time of posting there are eight bids for 013, the highest being £700.