I think, they had the same color un Korea. WWII was definitely the same as all the tanks came from the armor board specs right from the factory or tank depots.

I know post Korea the USMC went to a different color OD. It was always flat, (as opposed to Army which was semi glioss) and was more green less brown.


USMC



US ARMY


Colors vary a bit by light and camera. but this is as close as I could demonstrate. Army has brown tint, USMC doesn't.