Wow! That red & silver bike is gorgeous!
Mick Duckworth, in his book "Norton Commando," says of the Earl's Court show bike (the 1st Commando), "Little did the public know that it was a non-runner.... Nor would they have guessed that its all-over flat silver paint finish had been applied with car touch-up aerosols by NV experimental staff." p.26 Mick adds that for production, "The all-silver engine was also rejected, production bikes having their iron cylinders finished in traditional black. Mouldings were not painted but were self-coloured by pigment in the gel-coat resin. The standard overall livery was now Forest Green (often described as British Racing Green) for the fuel tank and seat tail with silver side panels and a black seat cover, but buyers could still opt for silver bodywork and the orange seat, as seen at the show." p. 41 I have a friend with a '68 which is Guardsman Red & the color is in the gel-coat. So, apparently silver, green & red were available in '68.
I've never seen an original silver bike, but in the photos I've seen in Duckworth's book & other places, it looks to be a smooth (not metallic or metal flake), almost semi-gloss finish. The first Commando I ever saw was in '69 at a dealership in Aston, PA. It was a customer's bike. The badge indents were filled & it was painted in Cadillac silver mist (flake) with hand painted 'Norton' script in bright electric blue. Awesome looking bike, but certainly not the thing to do to an original silver bike at this point.