First ever post and it's a cliche: Help me identify my father's watch? (Modem burner)

[AMDB2]

Ok long time lurker and horologeek here. I've never had much to contribute here, but always enjoyed reading what you all had to share.

So at last, I come to you all, wondering if you can perhaps help me identify the watch pictured here. I will preface this saying that I have spent a couple weeks researching the watch. There are no ref #s on the case, only the model number: 418212. This places the watch made 1947.

I have found a handful of similar watches, but none that are identical or definitively the same. Some have round buttons and 2 and 4, some read "telemetre" instead of "mileage," some were made over a decade earlier, etc/

My father remembers next to nothing about this watch. Though, as a stockbroker by trade, he of course remembers paying $400 for it sometime in the 70s or 80s.

There are no markings on the caseback asides from the crown and serial# pictured. I am sure there would be lots of fun stuff to discover if I opened it up, but I am not comfortable doing that. So, any help oh Sages of the Sub?

Thanks in advance fellas!