Hap, it looks like they are using eggs from existing wild stock and "conservation" broodstock, which I assumes means they are from hatchery reared stock that they know the genetics are from that area. If you mean that the areas that they are reintroducing had genetically diverse grayling in the same drainage then I don't know how they could re-establish from extinct genetics, and therefore, you could be right. I don't think there is any chance of re-establishing the actual Michigan grayling for that very same reason.