The 'debate' started in earnest around 35 years ago, with discussion and argument over the well-known colour photos of 'The Bottisham Four', as they became known. At the time, I was even involved, albeit on the fringes, as a certain magazine asked if we could advise on the actual colours seen in the photos, and establish if it was blue, or, as had only just been mooted, a shade of OD or other green.
This was because many reproductions, in magazines and elsewhere, were less than perfect, more so if the reproduction was a copy of a copy of a reproduced original transparency, where the upper colours did exhibit a blue cast, of various densities, depending on the printing at the time, and this varied, in the many different reproductions, between a hint of blue in what looked like a dark greenish shade, through shades of blue, to almost redish purple !
Of course, as a certain author had mentioned, many years previously, that the 361st used a distinct shade of blue, for which there was little, if any, evidence, there was certainly a case of the eye seeing what it wanted to see, and this 'colour scheme' grew from a passing remark, to being 'true', to the extent that every profile of the Group's aircraft showed this scheme, and every model was painted in the 'Railway Blue', with some kits including this scheme on the instructions, and even at least one airworthy Mustang (in the USA) finished in the same scheme !
I get down to the great Bottisham Airfield Museum when I can, and I've had long talks with the Museum's historian (who has an absolutely fantastic Bottisham and 361st FG photo collection, consisting of a lot of large, very heavy albums), and he confirms what we deduced from the 'Bottisham Four' photos all those years ago, both by info in his collection, and from first-hand accounts from the men who actually re-painted the aircraft at the time - the upper surfaces were (new) OD, darker of course than the weathered, older paint on the anti-glare panels, but where the AEAF stripes were painted out was very possibly locally acquired RAF Dark Green, but might have been even newer OD. Regardless of what was used to cover the stripes, it is darker then the rest of the OD, even if only slightly.
(Note that some units in the 8th and 9th Air Forces sometimes used British Army paints, if or when US OD was in short supply or unobtainable at short notice.)
The reason for the OD upper surfaces was that the 361st were supposed to deploy to the Continent as soon as possible after 'D-Day', and was intended as camouflage when on the ground at one of the rudimentary ALG's behind the beach head, with the same upper surface 'colour scheme' being scheduled for all of those FG's who would also deploy to Normandy, or have reason to be on a ALG during daylight - for example, if still based in the UK, but operating form a ALG during the day, and returning to the 'home' base in the evening.
As this was intended as ground camouflage, then it makes absolutely no sense to paint the aircraft blue !
From little rumours great news stories grow - I saw it in 'The Daily Mirror', so it must be true !