According to the lessaiz-faire attitude of the Japanese population, instead of suffering more in the clautrophobic cubes, the OG's of Japan took to the beaches (there isn't much sandy ones in Japan, mostly the "kuro" muddy or rocky type being a geologically young island country) and got their natural dark skins. Being genetically close, I was amazed to find an old photo of my youth. I recalled how quickly we, me and my sister, turned dark during the summer. It might be that many kids growing up in the countryside turn "dark" for the summer season, and then back to fair in the fall in preparation of the dimly lit winter. It must be that way all over Japanese countryside -- with ganguro kids returning from their summer vacations. Someone just commercialised it; it must have become hugely popular, as many young people could readily understand the joke behind it all.
So naw, I think the barbie-doll connection is just some post-production tidbits added to juice up the group, not how the whole thing got started !