P-51B Radiator Flap - colour of sides?

[Johnson]

Is there anything definitive on the colour of the sides (outer) of the P-51B Mustang radiator flap? The vent that lowers at the rear of the fuselage. Searching on the web and BM have drawn a blank.

 

various possibilities occur to me;

• Same as the underside (neutral grey for the plane I'm modelling).
• Zinc Chromate, either straight (yellowish) or mixed (interior green).
• Silver, either NMF or doped.

Cheers,

[72modeler]

Pretty sure the exterior surface of the radiator and oil cooler flaps were neutral grey on camouflaged aircraft and unpainted aluminum on bare metal aircraft. Restored Mustangs are  frequently finished in aluminum paint, so if doing a painted  restored P-51C/D, the two flaps would also be painted.

Mike

[Johnson]

Thanks Mike, makes sense. So, NG for my planes.