Yellowbelly or Normal?

[jrgh17]

So I loaned my S.O. my copy of "The Ball Python Manual" and she thinks that Patches may be a yellowbelly. Here is what the book says about the yellowbelly morph:

"This is one of the true mystery snakes as it is difficult to recognize unless you can trace the parentage. Most of its external markers are variable at best. Generally, there is a light spot on the center of the top of the head that may be either quite visible or obscure. The eyes are dark as seen in the wild type ball, and the tongue is pale. The neck, back, and tail patterns are also normal, but some specimens have a brighter yellow color. Look at the ventral and side coloration for your confirmation: the yellowish or whitish patternless belly forms 'triangles' of color intrusion into the side pattern, and a speckled appearance is sometimes apparent.
In order to determine if a snake that you suspect is a yellowbelly is indeed a yellowbelly, it must be bred to either another yellowbelly or to a normal snake. If a true yellowbelly is bred to a normal ball, approximately halve of the babies will be yellowbellies. If two yellowbellies are bred together, then one out of four babies will be a super yellowbelly (ivory) also confirming the heritage."

Obviously, from that, I'll never know unless I decide to test-pair her, but I'd like opinions. I'm not asking for a sure answer... I just want to see what people think. Here are some various pictures of Patches from different angles (hands provided by my roommate).

Here is a shot from the top:




This is the best tongue shot I could get:






I take that back. THIS is the best tongue shot I could get:






Here is a side-pattern shot:






Tummy shot:






And here, you can see the lighter spot on the top of the head:






So what do you think? All opinions are appreciated. I'm also posting this on the Cornsnakes forums (where I'm much more active), so if you're on both, please only vote on one.

As a side note, we are betting on this, of course. Don't ask the terms of the bet.