My limited experience is that even if you found minty Mauser grips you might have to remove a small amount of wood to get them to fit correctly, especially for the left grip.
I bought these grips for $23 as a test to see how hard it would actually be to make them fit correctly on my 1915 DWM before gambling on a more expensive set.
https://www.ebay.com/itm/25640373464...3ABFBMuobZ_4dk
I was happily surprised to find that there was only a small amount of wood that had to be removed around the safety lever pivot point, and the right grip required only the lightest of shaving on the top.
They looked good enough to me that I just kept them and didn't bother with buying more expensive grips. Part of that decision was the fact that my P.08 is a fairly nice looking shooter grade pistol and not a collector grade piece. Of course, caveat emptor, YMMV, etc but they're cheap enough to use as a test with not too much coin to lose.
-Bob