It could be that there was an HSV node with saturation set to 0.00 between the transparency output and the regular hair shader? Personally, I would never do that, but if there's no transparency shader, perhaps that's what the vendor did to achieve the trans. It's the only way I CAN envision using the regular color texture for a trans since it would make the color texture black and white (but only to the transparency) ;).

Laurie