I reckon the red in the hubcap is the same as the red in Holden grille badge, GTS badge, 5Ltr badge and the HK wheel arch trims.
I had a bunch of NOS bits all lined up and it was one red for all.
As for the GTS hubcap paint this is my theory but I think the hubcaps were all suposed to be Marne Grey (563-6911) a textured metallic suede.
I've see NOS hubcaps that are absolutely 100% Marne Grey and I've seen other NOS hubcaps where it seems they ran out of metallic additive so they just lightly dusted silver paint over a grey for a make-do metallic finnish.
Some were originaly very silvery and far from Marne Grey, I think it happened over time and it might have been a paint supply problem.
Its almost like someone lost the mixing instructions on how to make a metallic suede or maybe they never had the instructions.
It was only ever available ready mixed from Dulux in 1-pint containers so theres a chance the paint was supplied from the US.
In the US the exact same stuff is called Dark Grey Metallic Suede 4433-L.
I think they were all supposed to be painted the same but many were painted differently from new.
Another example of this is the upper dash area, it was supposed to be a textured suede too but I think only Dandenong did it correctly, Adelaide cars didnt even have a texture but they should have according to all the documentation I've seen.
Supply issues from the US would be one guess or maybe a local paint supplier won the contract over Dulon/Dulux and just made it up?
I'd say the design department originally wanted Marne Grey though because most of them are from what I've seen.
The only time you'll ever see and feel the original finnish is in the 1965 Dulon colour advisory sheet for the instrument panel colours. Several textured suedes are there including the black for the upper dash 563-6912