Well the cool thing about the Grey paint job is all the nice weathering that shows up... Just weather the green paint job apropiatley, and Bobs your uncle.
When you knock the glossy finish back it also helps...
Or some different color panel, that tells a story. I have some walk around books on these planes... They're almost indestructible, if you see some of the damage these things take and still they make it back home, it's insane... So they would definitely see a lot of wear and tear and repair in the field.