The rainbow curl art was drawn by illustrator by the name of Allison. She worked on the tail end of g1, g2, some G3 , puppy in my pocket , cabbage patch kids, and more. She has illustrated most if not all of the art from year 8-10 in the USA.
Ruth worked on a lot of the playsets, costume wear, twinkle eye ponies etc in g1.
But there were several illustrators who worked on g1 art.. we’ve met a handful at the Pony fairs before...
Also one pamphlet with the rainbow ponies does have an artists signature on it.. which I was told wasn’t allowed, so it must of been printed on error with it.