Banded horns, in general, are a 1790s, to about 1820-30 phenomenon. Carolina banded horns were made in the Alamance, Randolph, Moore, Guilford, Davidson, and Forsyth counties of NC.
The bands can be carved from the parent horn, or applied, as mentioned in other posts. Common materials for rings included pewter, wood, bone or antler, though bands made of horn appear to be most common. In addition, raised, "beehive" butt plugs were common, as were applied tips made of wood, bone or antler, pinned to the the horn. Screw tips were not all that common.
An internet search might turn up more information or photos.