My research into the US Navy schemes shows they weren't painted, but rather covered in soot as was the arrestor hook. The US engines were notoriously smoky, this being one of the drawbacks of the earlier Phantoms. The F-4S was a redeveloped and enhanced F-4J which went to some lengths to reduce the smoke trails left by the engines. I'm unsure how smoky the RR Speys were.\ said:They were made from titanium and double skinned.Cant remember how they we're finished but they were almost black.The flat panels on the fuselage above them were cut from titanium sheet.The arrestor hook was usually covered in black soot.