Southeast Arizona is thought to have 3 different subspecies of kingsnake converging in the same area: splendida, californiae, and nigritis. Depending on the exact spot you're in, you can definitely find all three down there. Some of the most famous herping spots seem to have kings that are integrades... particularly between nigritis and splendida. Many people theorize that these "integrades" are actually a dark phase of splendida. I have a friend who bred two kings from the area that appeared to be integrades (completely black on the top with hints of splendida banding on the sides) and all the babies look to be pure splendida with bright and complete speckled bands.
So, to answer your question, splendida are definitely found in the area. depending on the locale, they maybe pure splendida, an integrade, or a dark color phase.
I hope this helps.
John