Here is my vintage Omega Seamaster Calendar. When I got this watch, it doesn’t have any strap and I decided to fit it with a crocodile black leather. The watch was running around 30secs late and yesterday I had a watch repair guy inspected it. He tweaked something after prying open the caseback and it’s now running 10secs faster. He told me to revisit him again if it is running late and he’ll do something on the pinion wheel.

So far so good! Here are the pictures:

 

Very nice! It's probably from the late fifties, as it's a full-rotor movement

Great dial condition

 

Thanks for your nod! The date changing mechanism is superb for its age, need to move back and forth from 11pm to 1pm.

Here are some additional details:
Cal 503
Movement 14896xxx
19 jewels
19800 beats

I love the patina on both the dial and the calendar window. Hope it is not a redial.

The watch belongs to my late Dad who passed away in the early 90s. Never got to ask the history. He has 2 other Seamaster from the 60s.