I’ve turned up a number of formulae for US WWII era “Interior green” and the British “interior green” fuel-and-oil-proof paint which was a different color and served a slightly different purpose. I’m going to post the formulae now, explanation later.
US green zinc chromate (Interior Green?) from Tamiya 1/48 F4U-1A cockpit, etc instructions:
2 parts XF-3 (Flat Yellow) + 1 part XF-5 (Flat green). I’ll have to make some of this and report what color it is. US “Interior Green” A/N 611 wasn’t a paint available in cans, it was a standard color that zinc chromate was supposed to be tinted to using black pigment.
Bell Aircraft used a bronze-green finish on interior surfacesr of of P-39s and P-63s. I don’t have an FS number that approximates it but here are a number of formulae offered by Eduard for their 1/48 P-39/P-400 kit.
Bell interior bronze green:
Tamiya: 1 part XF-4 + 1 part XF-5.
Revell AG 2 parts #60 + 1 part #362
Gunze Sangyo H405.
I’ll post the British Interior Green mix from Tamiya and Revell AG paints tomorrow.