My opinion is yes, I would say it's a YB. Here is why I think that. The black belly tracks on a normal very rarely come all the way to the central belly scales, and almost never come to the central belly scales at the base of the brown pattern, usually only where the black meets the belly. This snake displays both. Some YB's are great examples of the morph, this one may just not be that uber example we are used to seeing.

There is one way to tell for sure. Pair a YB male with her and see what happens. Heck you should be able to tell just by breeding her to a normal, but if you get an ivory from breeding her to a YB male then there is no second guessing.