GMT 1675, circa 1977, Mark 5b (Mark V variation)

[springer]

The is a GMT 1675, serial 5.7 million, circa 1977. The dial on this GMT is another variation of the Mark V era dials. It is different from the Mark V or Mark 5a in that the coronet has a different shape and the O's in chronometer and officially are round and not oval shaped like the O's found on the other Mark V dials.

I refer to this dial as the Mark 5b but it might be referred to by other names elsewhere on the internet. I believe I have even seen this dial referred to as a Mark 5c.