The only registered trademark that I could find for any common plug was "darter"--and that was orignally trademarked by Creek Chub in the 1950s and is now owned by some company in Alabama. It could be what PRADCO was called before it was called PRADCO.
Brad used to put "tm" on the label next to Hawg Hunter Lures, but I can tell you with 99.9% certainty that he never officially registered it
