A couple thoughts. The Ark CNBG (there is an extensive thread)were original CNBG brought to the Ark hatcheries years ago but which have undergone local adaptation through numerous generations. They are still CNBG that have adapted a little. This does not address any particular hatchery/seller who may have crossed them with BG or GSF etc.

Introducing a non native species or subspecies to a new location can give either positive or negative results. It can also improve the existing population or make it much worse through interbreeding. Take the dice and roll them if you like. Readers just remember you can roll 7s or snake-eyes.