Forend moldings of any sort are rare on what we tend to think of as the "classic" east Tennessee style rifle, ca: 1830s on forward. I am sure there are some. But they don't seem to be typical based on what I have seen. Most often, the only moldings on these guns are on the cheekpiece.
There are a number of earlier looking iron mounted guns, ca: 1800-1820 that appear to be made in either Tennessee or southwestern Virginia and North Carolina that have forend moldings and/ or lower buttstock moldings. James Levy posted one last year from the Florida museum that had concave groove forend moldings as I recall.
If I were building an 1830s East Tennessee gun and wanted moldings, I guess I would keep it a simple incised line or simple relieved line. Sort of a slippery slope though - finding a graceful way to terminate the line so it keeps the lines flowing - because fancy finials, snake tail finials, etc, that are used on other types of guns to terminate moldings would tend to look out of place on a Tennessee rifle, based on most originals I've seen.
Guy