WaterfowlForum.Net

According to the internet there are three.
Google "dog trainer Lenoir NC"

1. Keith Walker master dog trainer
2. Carolina Mountain Canine, home of Bone Rouges Dog Training
3. Pennell Dog Training

Call them and ask if they train working retrievers and if they don't ask who does.
#2 is open until 6pm today.

I'm in Illinois and can not vouch for any of the trainers listed. All I did was google it for you.
Those trainers only do potty training for all I know.
Hopefully they can steer you to a trainer that does "retrievers for waterfowl hunting".
Make sure you make that clear when you talk to them.
Good luck.