I've been using the 383 green PN 34094 from Rapco Parts. Nothing will match perfect if the set is faded, but you can get a spray can and spray some into the cap to use for brush touch-up or use the spray can to "Dust" it in and blend it a little.
Another quick note: if the set is faded, go over the whole thing with a coat of spray can Flat Clearcoat. It will help blend everything together.