The only way to tell is to prove it out. I would try breeding to a normal female; if ~half of the babies look like daddy then you have something going on. If they are then bred back to each other and you get a super form ie BEL, than you can call them whatever you like.
Thanks everyone for the replies, I haven't seen too many fires or yellowbellies or any of the more hard to spot morphs in person so I thought I'd ask opinions.