Until very recently, I thought the 42mm size has been maintained since nearly the beginning, but now I'm discovering new information. Was it 39mm before 1965?

Does somebody have picture comparisons of the size difference?

 

Believe 42mm includes the crown guards after 1965

 

Per Moonwatch Only book ref 2915 thru 145.003. Excluding crown and bezel 38.2mm. Bezel diameter 38.6mm (steel bezels) and 39.7mm (black bezels).
This book has more info than anyone should REALLY need to know

 

(The bezels from 105.012-63 on were also 39.7mm. Peatnik, you are correct, crown guard case diameter excluding crown 42mm.)