BRONTO's advice is correct. Although a stunning number of modelers make the mistake that Phil is suggesting. You can count on one hand, the number of pre-war photos of vehicles where the interior hatch surface wasn't painted the same as the exterior camo color. Think about it -- you camo your vehicle completely but when you want to ride without being buttoned up, you show 3-4 white/ivory/silver hatches to enemy observers?
99.9999% of the time: go with the exterior color. That time you want to veer, you better post an accompanying picture. And don't look at other models -- those builders have made a mistake.