The look of the plane is fully atypical: aside the gun barrel, the shape of the ventral cooler, the absence of radio mast and landing gear doors, the unpainted prop blades, the small star with silver-black (or white-red?) outline are unusual characteristics. 
It is not known if other K-37s resembled to this one.

The image seems to show a non-standard low-contrast camouflage, but it can't be excluded that this is wrong and the uppersurface was overall green, as common use on other types before the war outbreak. In this case, it should have red stars on the wing uppersurfaces too..