That's good, since that sort of guessing leads to a fair number of mislabeled animals (of other species; I couldn't say how bad this is in ball pythons specifically) on the market. Even a "looks like a..." hypothesis can easily turn into "some knowledgable sounding breeder told me it is a ....". Given that the odds of any given ball python not finding its way back into the market at some point are slim, that label can stick.
Unless a person is willing to test breed it to confirm, it is probably best not to know.