Yes you can use the config files for each skin replacing the paint shader, this is a good example of how it's done (check out the paints on the S1)
2002-03 Subaru Impreza WRX hatchback (GG) Installation Using 7zip, extract two folders from the 7z to your Assetto Corsa cars folder creating cars/subaru_impreza_wrx_2002/ and cars/subaru_impreza_wrx_2002_s1/ The 7z file also contains...
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And if you need to do masks combining different finishes you need to use the _map file, using the RGB channels
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