I've actually desaturated the underside colour a fair bit, it is normally brighter than that. Soviet colours are a bit of a minefield, lots of differing sources, not much original source material and the colours faded a lot as well. I can desaturate the underside blue a bit more though.
The spinner, arrow and flag colours are just my educated guess. The flag is likely to be blue because of the Mongol Empire flag connection and I figured the other markings would match. The shades of grey in the photo don't contradict that assumption. However the spinner could in theory be dark grey camo or some other colour. It is also possible the arrow was originally painted white by another unit and was over-painted grey when it was transferred. However this seems unlikely to me because it is too neatly painted, no one doing that job would bother to mask the arrow off, they'd just block out the area.