[Guest]

Well, there is no need to be in RLM standard, because its German color standard (derived from railroad standard BTW).

Here is cockpit color.

http://www.simmerspaintshop.com/page-RGB-colors-UK.html

Its 9th from the top, it says:
"Aircraft Grey-green after 1940 Interior finish"

But notice that IL2 has very weird color portraying, so it's very hard to pick exact color which can be shown in-game as exact one.