Remember those unsubstantiated rumours that Tigers were appearing on the front in (red) primer only? It sort of co-incided with the orders of late '44 for the armor manufacturers to switch from the yellow to green basecoat on the components. What if this green basecoat was actually the primer color (primer can be colored besides red). Brown and dark yellow was to be added when the tanks were assembled, saving some time and yellow paint. If some tanks were hurriedly shippped out upon completion without the additional colors, then they would indeed be in their primer color - green, not red. This could also explain the difference in the green color found on late production tanks. This is just my theory...thought long and hard on it.