Color Of 1914 Mauser Grip?

[SAKIJOE]

I HAVE IN MY COLLECTION A 1914 MAUSER PISTOL WITH TWO ORIGINAL MAGAZINES AND THE ORIGINAL HOLSTER.
PISTOL WAS MADE IN 1915.
IS A MILTARY ISSUE
THE ONLY PROBLEM IS THE COLOR OF THE GRIPS/ THEY WERE STAIN IN BLACK.
BEFORE I DO ANY THING WITH THE GRIPS. WAS THERE IN ANY PERIOD. DID THE GERMANS CHANGE THE COLOR OF THE MAUSER 1914 GRIPS?
REGARDS.................