As Bob and Mike said above, I have read that along the southern coast, smoothbores were most common. It was cheaper to buy an import gun landing at a town like Norfolk, Wilmington, Charleston, and Savannah than to have someone make one. Once you got inland, the transportation added enough to make local gun building worthwhile. I noticed that books like Bill Ivey's don't show any gunmaking "schools" in the coastal areas like Wilmington. I know there was a gunsmith in Wilmington, as I have seen a period advertisement.
Also, due to the dense nature of the coastal forests and pocosins, it is my understanding that shots were short range and often fast moving affairs. The smoothbores worked just fine in that habitat, and allowed the versatility of using it for fowl, large or small game. Even today, hunters often go afield with shotguns in the coastal plain.
If anyone has any period advertisements or writing about gunsmiths in Wilmington, NC, I'd love to hear about it.
Bob, sounds like your family were Highland Scots if they settled that area? The Scots Irish seem to have all gone as far west as possible in NC to live the way they wanted.
God Bless, Marc