Gray treefrog habitat specific coloration

[Pactolus]

I got my grey treefrog tadpole from a vernal pool in an upland karst area of Fayette co KY near some shady woodlands, and all the tadpoles there were very dark brown, some almost black without any bright colors at all. From pictures I've seen, gray treefrog tadpoles are usually quite a bit lighter colored and greenish, especially as newly morphed froglets. Mine is very dark and only gets a little bit lighter colored at night. Is it possible for a population in a specific habitat to develop and keep a specific color over hundreds (or thousands) of years?