Yeah, looks like a perfectly normal T. radix. Often times, local natural selection can cause two different species to develop similar characteristics, (convergent micro evolution) even if they aren't hybridizing or genetically the same. I see evidence of this in the south end of the Puget Sound near Olympia, WA. Puget sound garters in that area are very blue. Many northwestern garters in the area are also intense blue, even though no hybridizing is going on.

It's therefore not surprising at all that the butlers and radixes in your area may share similar color/pattern.