Here it is.

However, when I checked other examples on the internet, it became evident that the holster I saw was not of a Mauser C96.
The Mauser C96 wooden holster's end that fits into the pistol grip is slightly angled.
Photo from Wikipedia
http://en.wikipedia.org/wiki/Mauser_C96

So, I did a bit of snooping around. The wooden holster that I saw in the market is made for the Stechkin automatic pistol.
http://en.wikipedia.org/wiki/Stechkin_automatic_pistol

From rusguns.net

You will notice that the groove that fits into the pistol grip is almost straight.
The Stechkin Automatic pistol uses the same 9X18 cartridge used in the Makarov pistol,BTW.
Best-
Vikram