I was posting those more with an eye toward the overlap between northern/southern strains than with respect to that West Virginia fish being wild or not. I agree with you on that, especially in that it had such a dark gray underbelly. As you can see from the Norfork fish, even a stocked brookie should be colored up if it's had time to go wild.
The relevant question is probably not whether or not the fish was stocked but rather whether it was *recently* stocked. West Virginia has wild fish that should be colored by the time they are that size if they were born in the river. Likewise, a stocked fish that was stocked small and grew up in the river will also be colored. I think a fish of that size and that generally dark color most probably was a recent stocker (but I'd leave a 10% chance that it was just an unusually dark wild fish).