i think the yellow(my thought) i an anticorrosive paint...
I think you're right. When we paint airplanes, we prime them with a type of self-etching, anticorrosive primer (*I* don't actually paint, so I don't know the proper names of the materials LOL. Dammit Jim, I'm an electrician, not a painter!) but I think it's a zinc something-or-other. Maybe that chromate stuff?
At any rate, it's just about that color. Even if the screen armor wasn't painted with the same type of primer, it looks as though they were trying to simulate exactly that.
Just my twopence.