1939 Oysterdate - thoughts?

[shocken2]

Hi all, new member seeking some info on the pictured Rolex Oysterdate. This my only vintage Rolex and frankly I bought it without knowing as much as I should have about this type of watch. I’ve done some research since then and have found a small number of very similar models online, but not a lot of solid info on them. It’s similar to a bubble back, but I don't know that that would be the popper classification.

The number between the lugs (where the ref no would be on a modern Rolex) is 6056. I’ve searched for info on “6056” Rolexes and have seen a number of different models that all use that same number. All seem to use a very similar 30mm case and I suspect that this may be a reference for the case alone, and not the specific model. The serial number (705xxx) dates it to aprox 1939.

I’m not actively trying to sell the watch, but would also appreciate any insight into the value (several of my vintage watches may have to go in the near future to fund a an Explorer I, or a Speedmaster Pro, or both). I took it into a local vintage shop lately and was offered $500, but didn't want to sell or make a counter offer without knowing more.

This is certainly the place for experts on this kind of thing and I’d love to hear from some members with more knowledge than me on the topic! Thanks!