Inherited Dads Luger/ Identify

[spleeft]

I just signed up here, and plan on utilizing the forum quite a bit. It looks like you'all have a great forum !
I wasn't sure where to start, so I'll just jump in right here.
Here are pics of the Luger. I'm pretty sure my father got it from my Grandfather ( WWII vet ) but it looks like, from the bring back papers , he got it from someone else. I am interested in the history of the gun mostly, as I plan on keeping it , but an estimated worth would be nice for insurance purposes. I have the Bring back papers with it also, but not sure if I should post it with the names in view, ( probably doesnt matter )
I'm particularly interested in the receiver markings, I couldn't find them using a google search. Also the serial numbers look like they all match , but I have not dissembled it yet.
I can retake any photos if need be. ( I didnt see the "how to take gun photots" soon enough !)
Thanks in advance for any insight !