Thanks for your replies, guys. Srecko's thought on different colours for wood and metal surfaces sounds interesting. The very strong differences in hue are nevertheless remarkable, especially in the second photo. It seems that no measures were taken to unify the outward appearance of the cowling and the rest of the plane. This would be a strange habit for a peacetime air force...maybe it was less obvious when seen in (coloured) reality or the respective unit commander deliberately viewed this effect as some kind of two-tone camouflage..seems we will never know
