Probably not a "solid answer" you are going to get anytime soon. There are over 1000 cars in the game, with multiple colors being available for most premium cars and some standard cars also having multiple colors.
Red from Ferrari and a red from Alfa(or any two manufacturers) may be "the same color" but with a different name... Ya know? I have over 20 different "matte" colors and I don't think that I'm close to getting them all by any means.
