I can't help with the camouflage colour Lucas, as US colours for that period and theatre are definitely not my strongpoint! But I can help with the internal colours. The wheel wells, wheels, inside of wheel doors, the landing gear legs and the inside of the wing folds were Insignia White. The aircraft built by Grumman had Bronze Green cockpits, with the internal area to the rear of the gun turret in Interior Green, as was the inside of the bomb bay and bomb bay doors. The inside of the cowling and engine bay was Light Gray.
Those aircraft built by the Eastern Aircraft Division of General Motors (TBM's) had Interior Green finish on all the insides of the cockpits and fuselage, with the bomb bay, bomb bay doors and the engine bay in yellow zinc chromate. The wheel wells etc were as described above.
That's some fantstic work you've done so far in such a small scale, especially on the engine. I would have gone cross-eyed by now, and learned a few new swear words!!
Terry.