New to Lugers amd Forums

[Oldguy51]

I’m new to Lugers and the forum. I don't know anything about forums so if I am doing something wrong please let me know.

I recently purchased a P08 from my nephew who needed to sell it. Pictures attached. I’m interested in learning everything I can about it. From what I have gleaned from the forum I think I know the following but would appreciate any corrections or additional information.

-Made in 1936 by Mauser.
-Early 1936 production because no letter after S/N.
-9 x 19 (9mm Parabellum) caliber.
-Shooter because re-blued, wrong grips, not all parts match S/N.
-Military issue because of proof marks.

I know it will never have any significant collector value but would like to return it as close to original as reasonable just for my own enjoyment without putting too much more money in it.

-Can anyone recommend some reasonably priced walnut grips to replace the plastic ones? From what I have read, some of the replacements are junk.
-Does the hand scribed “75” on the side plate indicate anything significant like it may have gone back through an armory and had this replacement side plate fitted to this gun or is it just something someone did along the way?
-Would it be worth it to try to find a side plate with numbers to match the gun?
-I would like to get an additional magazine to use when I take it to the range. Are there any decent new replacements available or should I buy a used one?
-Does anyone have any other suggestions for “aging” the gun or doing anything else to return it closer to the condition it should be for its age?

Thanks and sorry for all the questions.