The Wings Pallette site has some color plates of P-35's and P-36's in the camouflage for the war games of '39 and '40. They would suggest that one of the "colors" might be the NMF. I also found a list of colors used on the P-36's that were at the Cleveland air races in 1939, they are, Sand, White, Light Blue, Sea Green, Dark Blue, Dark Green, and Dark Olive. There are also three colors that were mixed, Dark Purple/ Neutral Grey, Neutral Grey/ Black, and, Black/ Rust Brown.