According to the E&R Manual (AN01-60JE-2, p. 406), the appropriate finish color coats for the pilot's compartment are as follows:
Metal floor areas: No finish coat required.
Wood floor areas: See Notes NOTES: One coat of SPEC NA2-1301 Non skid surfacer
Pilot's Seat: Dull Dark Green
Control Handles: Corrosion resistant, Cadmium or Zinc plated require no finish coat except for knobs finished in accordance with the applicable drawing
All other areas, STA 101 to STA 184: Interior Green NOTE: Areas not normally visible require no finish coat.
FYI: STA 101 is just about the forward end of the windscreen and STA 184 is just about the aft end of the sliding canopy (canopy closed).
Now, having posted that, it should not be construed to say that every P-51D you will ever see has been maintained to the manual. There may indeed be differences and if evidence surfaces that provides for other alternatives, then you have another option. Of course, it's your model, you can paint it day-glo pink if you should choose to. It won't be prototypically/historically correct but it's your model.
Edited by TimC, 20 July 2012 - 08:41 PM.