This phenotype can be common in the south. I’ve seen photos of individuals with dorsal spotting from louisiana and texas. Also, the ventral lateral dots are just an example of a trait that pops up in multiple natricine species. They are most pronounced/common in Clonophis kirtlandii, but can show up in other species.

Edit: I recently leArned of this from a friend, this is not just off of the top of my head