I started colorizing this picture:
As far as I know photo shows former RAF Airacobras Mk.1 in Vaenga airport.
This should be instruction sheet from AZ Model (found at internet):
My colors so far - yellow number over white (or alluminium/silver) surface - usuall appearance I found at the internet:
Colors are not definitive, just to get overall impression.
I found pictures at the internet where outer half of the wing is Olive Green (RAF???) or red. IMHO, the whole wing is one quite relective color. The bright area is the reflection of the shining fuselage on the wing and also on the fin. And the darker area is reflection of the cloudy sky.
Note solid "shadow" on the left part of the second digit of the board number. It does not look like "5". Plus I miss there horizontal "shadow" in the middle like on the "9". That second digit looks more like "6", similar to "60" on the next plane.