My opinion.......
I don't think they are a cross, so to speak. I think they are more of a natural variation of guttata that developed over a long period of time, much like the Keys corns. I have no experience with the ranges or natural history of the areas that the Kisatchies inhabit but draw my conclusions from the writings of others that have that expertise.
With that being said, there may be an evolutionary link in the guttata line that branches off of the limb that corns and Great plains rats share. Not a cross so much, but more of a link between the two.
Ronda of Northwest herps has some pics on kingsnake.com's photo gallery of Kisatchies.