it says Zinc Chromate,,,,,,but, I don't know why
I only know enough about Hueys and Cobras to get one of each done,,,,,,and even then I am cheating and making my Huey an Air America bird, and using an even more ancient MicroScale 1/72 decal for my Cobra
I am building my Helo's to this standard "Two rotors, looks like a Banana, that is my H-21, one rotor, looks like a tadpole, that is the UH-1,,one rotor, sorta fat, UH-34, one rotor, really fat, CH-19",,,,you get the drift, lol
Rex