1939 Mauser Luger 42 code

[CopperK9]

Bought my first Luger the other day, unfortunately we have a 7 day wait in my state for handguns so don't get to pick it up til next week.
Looking for a little more information and approximate value on it. Year 1939 with the Mauser code of 42, from what I could see all the parts had matching serial number of "04" matching the 4 digit serial number. 3 eagle stamps by the barrel. Came with a brown holster and two magazines, one looks original, other is aftermarket. Some of the bluing is worn off at wear points on the side but otherwise looks to be in good condition. Paid $1200. Seemed to be a decent price from what I've seen online but I'm no expert. Wasn't looking for anything perfect, just a decent gun that can be shot occasionally.
What does the brown leather mean? I'm used to seeing all the WW2 German gear in black only.

I'll post pictures as soon as I get to pick it up. Any advice or info is much appreciated, thanks!