I think that they are just going for a slighty different look on a few aircraft. I have just had a look through the Air 2000 file on a.net, and as far as I can make out, only 3 in the AMM fleet currently have the green titles. OOAW, OOAV and OOOX.

Take Go as an example… not all of their fleet was the same color, nearly evey aircraft had a different paint scheme on it.