Ayup @Che Guava me owd fruit!
Risking a 'train wreck' here, but, it's my considered! opinion that if somebody is trying to do nasty things to you, with things that a.) HURT or b.) go BOOM! close enough is good enough. Don't care how many official rules there are, if somebody is chucking bullets, bombs or shells in your general direction, grey's grey and blues blue, end of.
Regarding your billious yellow, (great name, get it registered and sell the rights to games workshop!) my brain tells me (don't take too much notice, it lies!) Chromate Yellow and Chromate Green came into being from the late 1920's, early 1930's when U.S. aircraft production switched from primarily timber to duralamin, though I don't think the likes of the DC.1 and 2 used anything to 'protect' the metalwork. Know that some companies favored yellow over green and vice versa. Republic used both! at least on the P-47.
Talking of heaving what are your thoughts of the true colour of Olive drab.....................