You are still correct, they are western terrestrials, but they are a subspecies of them, the wandering. The western terrestrial garter name applies to all thamnophis elegans.... and all of the subspecies have their own common names, thamnophis elegans vagrans being the wandering garter its the same as how all of thamnophis sirtalis are called the common garter snake, and all of the subspecies have their own names (red sided, red spotted, puget sound, eastern, etc etc...)

hope that helps a little!! cool finds!