I'm really no expert by any means, so this is just my personal opinion from what I have seen.. I would not think this is a Yellow Belly from the pictures alone. It's very difficult to determine by these pictures. It could just be a nice Normal with many flames and a clear belly, or it could be a poor example of a Yellow Belly. Hopefully more experienced people can give their input here.
Were you sold this snake with the impression that it was a YB or did you buy it as a Normal??