The grey is probably the most sought after colour for the period since the team bikes were that colour. Get drops back on it and clean it up. It might only be Carbolite 103, but that's still a damn site better than that 18-23 steam pipe that Raleigh used to do around that period.
I'm looking out for a cheap one of those to fix, I was thinking of doing that with my 501 tubed Pug, but it's just too damn nice.