If you find a good web site about banana Cal kings, please post it. I haven't been able to find one, though I have not looked very hard. It is possible that banana resulted from goulash genetics -- throw everything in the pot and see what happens.
From the looks of the banana Cal kings that I've seen, I think that the striped mutant gene is in the mixture. But I'd only be guessing about what other genes are in there.
A dot-dash Cal king usually has a striped mutant gene paired with a normal gene. As far as I can tell, there is so much variation in the expression of the striped mutant that you often can't tell whether a particular snake has one or two striped mutant genes in the gene pair. That would make the striped mutant gene dominant to the normal version of the gene.