isn't there an issue with painting the topside of the aircraft any colour other than white anyway because of the heat generated in the cabin?
Repainting the Sentry in Barley Grey caused a fair bit of extra expense to confirm that the aircraft mission system cooling systems could cope with the change of thermal profile caused by the new finish. (All to do with the reflectiblity of the surface - some finishes are designed to reflect radiation - others absorb it).