Maybe it means unbleached? Dd wears organic clothes regularly, and they are not pastel colors, some are color-grown (cotton that grows in colors), an enviro patch or something. She has one outfit that says "from little acorns grow tall oaks." She's adorable in it.
No, you can't really tell. Unbleached is different from organic--you can have unbleached, non-organic clothing. Check out www.hannahandersson.com. They have tons of organic clothing that looks exactly like any other clothing (very good quality, though).