Made a blind bid net based on five watches at an auction in Yorkshire and whilst four were odd balls this one turned out trumps. I do not believe its been opened since it was bought, although I think the crown has been replaced at some time
Oops forgot to say - its a 501 and the sweep hand is there but the shot was taken at f32 with a 13 second exposure
Nice catch. FWIW a crown cannot be changed properly without opening the watch to access the movement, so there is a hole in your theory
