I think your wash looks just fine. It doesn’t need to be overstated…just enough to bring out some detail. The colors of your wheel bay look okay for an AVG bird. I’m assuming that’s what you’re building out of this P-40B/C. The flap assembly could work fine as it is although I would probably keep it the same color as your wheel bay. I understand a lot of the time a certain color paint would run out and they’d use whatever they had that needed to be used in its place. Since the AVG P-40s were originally supposed to be sent to the English, they came with the Dupont equivalent of the English color schemes. But I imagine maybe at some time that touch up paint might run out. So if you left your flaps the way they are I suppose you “could” argue that point. 
I just finished a Hawk earlier this past summer, and if you’re interested in taking a peek thru a WIP then I’ll drop you this link to it:
http://cs.finescale.com/fsm/modeling_subjects/f/2/t/158668.aspx
I made it as thorough as I could. I scratched a lot of what’s in it, and I focused hard on getting the colors right since that’s one of my quirks.
I’m working on another one right now…I wanted a Pearl Harbor Hawk too. You can see that one going on right now on the main page. If you have any questions at all, just ask. It’s no trouble. =] I’ll help you with what ever I can.