The source of the clownfish will not matter, clownfish are gentically encoded with the associating to anemone.
They may take sometime to associate with a BTA if that is the pairing you are going for (assuming you are talking about A. Ocellaris or A. Percula), but that is simply because they are not gentically encoded to associate with that anemone in the wild.
Buy the clowns you like, match them with the appropriate anemone, and they will associate, almost guaranteed, and almost right away.