Jason, Nice start to your 'Stang. An excellent kit and choice of subject for your 1st aircraft model.
As Jessica alluded to, the interior of most USA WW11 aircraft was post 1942-43 was Interior Green. It's a much brighter/Brownish color then Green Zinc Chromate. I've posted a few pictures of one of my brothers P-51D builds. He's done a ton of research, and has the interior colors down to a science.
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Also the turtle deck behind the seat is various shades of flat black.
The Engine compartment is basically Green Zinc Chromate, while the Oil and water tank compartment for our purposes is NMF
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The Wheel Wells and tail wheel usually were Yellow Zinc Chromate
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I'm really impressed with your machine guns. They look spectacular. Same for your custom made belts and harnesses.
Looking forward to your next update.
Joel