However in order to win an infringement claim you'd have to show that they constituted a substantial part of a work and that the colours were copied and not derived from a third party source or coincidentally the same. The usual civil law test is the balance of probabilities.
I think a more likely claim is that the matching colour scheme were a trademark infringement, an unlicensed use of trade dress (jurisdiction dependent of course). AFAIK DMCA takedown notices don't work for trademark infringement though?