It also matters if you mean a USMC jeep or an Army jeep.
War Department OD was different from the Service Green used by the Navy Department.
As Carlos points out, additional colors were made available to at least some of the Order of Battle for Operation Detachment. Which units took the time to use those colors is largely apochryphal at this point.
Once Marine units had crossed the ithmus at Suribachi, ther ewas a pause to collect and reorganize for the push NE to secure the rest of the island. Once past Airfield Number One, the terrain was more suitable for camo painting, and there would have been more access to paint stocks (no matter the owners thereof).
Sadly, the people present were much more occupied with their present task than considering the frustrations of people wanting absolute answers 75 years later.