Viet Nam era UH-1D engine compartment color question

I’m presently working to the KH 1/48 UH-1D kit that is a real jewel but have a question concerning the engine compartment and the interior engine cover colors specifically for the Nam era helos. The instructions call for FS 36231 but I have a hunch it may be a different color like interior green.

The IP has the wrong color listed as black while Nam ones were in grey so that one I got right so any help will be appreciated.

Interior panels should be zinc chromate green, FS 34151.

My suspicion has been verified. Thanks Gino!