There are plenty of Alembics around with the headstock laminate of a different wood from the top. Most of the ones I have seen are from the seventies, when that feature was more common; most had zebrawood headstocks, I think. As for nowadays, you are correct, most Alembic basses have the same wood for both headstock & body. Your bass may have been custom ordered that way. Mica will be able to look up the bass' history when Alembic goes back to work next week after the holiday. Coco Bolo can be pretty reddish at times, I wouldn't be surprised if that's its natural color.
Valentino