Estimate on an inherited Luger

[naidirem]

I was wondering if I could find some more specific information on a Luger that belongs to my family. The executor will be having it appraised and I will have the opportunity to purchase it but I'd like some opinion of what I might be having to pay for it.

Based on some quick research, I have figured out (right or wrong) the following things:

It is stamped 'Germany' on top of the toggle.
It has the C/N stamp on it in two places (I think).
The safety is marked 'Gesichert'.
I believe it is chambered in .30 Luger since I tried to chamber 9mm rounds and the bullet would not fit although they loaded nicely in the magazine.
The gun is stamped 77xx in two places and have matching xx in other locations.
It came with a holster but the holster was made at a shop in Chicago in the 20s (I think).

The family story on this Luger and some ofther handguns is: My Great-grandfather ran a towing business in Chicago in the 1920s and 1930s. He and his workers would search vehicles they towed and cinfiscate any firearms found. This Luger was among them. The holster has the name Pat written on it and a date of Nov 13, 1926.

I am will try to include some pictures.