Yep, from Hancock in a big ol' gush:

Quote Originally Posted by Hancock
You are doubtless wondering why our objectively green-hued friend here refers to himself as a Kojin of the Blue. The answer is quite fascinating, really. The Kojin language has many similarities with ancient Hingan, you see, and in ancient Hingan, the word for green, “ao,” can mean green and or blue─though I do the word a disservice by even attempting to translate it, so steeped in meaning as it is. Why they elected to keep on calling themselves the “blue” in modern times is anyone's guess─I for one would have much preferred “kojin of the ao”─but one theory posits that they prefer the sound of the word “blue” when spoken. Another is that they are physically incapable of distinguishing between the two, which would have interesting implications in their everyday lives...
Hancock seems to prefer subs over dubs.