Vintage Rolexes - Help required

[oldmisog]

I'm a new member and am seeking help from anyone with a knowledge of vintage Rolexes.
For some years I have owned two watches - an 18k Rolex Oyster Octagonal and a SS rectangular Rolex from the 1930's. I had the Octagonal serviced and the Rolex engineer told me that the case was hallmarked Glasgow 1926. I read that this model was launched in 1926 and I was wondering how I could learn more about its history. The movement is original but the bracelet is a later addition (1940's ?) as is the dial.
I know very little about the rectangular model except someone once called it a 'Dolphin' - any comments would be very welcome. Thanks, John.