As mentioned, apart from one, they all appear to have the dark yellow as a base colour, with a very heavy mottle/stripe of the dark green and dark red-brown, allowing only small areas of the yellow to show. The one with 'squiggles' all over it I presume has been modified locally at the time, and looks like the 'squiggles are also the dark yellow.This is possibly confirmed by the tones in the terrain shown in the photos.
(The last one shown, the Mercedes, is an earlier period, in grey, confirmed by the uniform style.)