Perhaps he/they (Caidin, and the aircrews concerned) meant the yellow front cowling ring on the FW190's encountered?
As for the other schemes quoted, it does seem bizzar, but, who knows how a 'colour' might have appeared, allowing for the light and conditions at altitude, and in the heat of combat? It's not the first time I have heard, or read, about such things, when authors, sometimes themselves the pilot(s) concerned, have described, for example, "..the black belly of the Me109...", when it is known that the aircraft concerned was not 'black bellied', but in one of the 'standard' camouflage schemes. It is irritating though, isn't it?