Speedking identification help

[SPDking]

Hello All,

This post will be my introduction as well as a request for help. I have an Oyster Speedking that I think is from 1942 or so, but I am a total novice to Rolex knowledge and I haven't been able to find an online database that would allow me to pinpoint this piece. This watch belonged to my maternal grandfather who I never knew. Not many folks are left in my family, and as I have no emotional attachment to this Rolex, I am probably going to sell it. About eight years ago, I sent it to a watch repairman in New England, and he did a general service on it. It runs great and keeps accurate time; I just don't wear it or enjoy it as I am sure a collector would.

Anyway, I would like to open the case back to take photos and see what numbers might be on the inside if that would reveal more info that a potential buyer might want to know, but I don't want to do that if it is too difficult or if I might damage it.

Attached are some pictures so you can see what I am talking about. On the outside back of the case are the markings "Stainless Steel R.W.C." and what I think is a serial number "203093." The adjusting/winding post says "Rolex Oyster" but doesn't have the Rolex crown logo.

Thanks in advance for any info about opening the case back (how to do so and what I might find there in terms of engraved data). Any other general info will be appreciated.