This is my understanding from what Jones said about it on the E! True Hollywood Story on the Dukes... Over the course of the First Season, Jones intentionally grew a beard to avoid Cooter becoming a cliched character. Before filming began on the Second Season, Jones was ordered to shave off the beard, which he did (presumably) reluctantly. However, as filming progressed on the Second Season Jones grew the beard back and was again ordered to shave it off. This time, however, he refused and walked off the set in protest. Eventually, after four weeks, the Producers (or whoever) caved in and Jones returned to the set with his beard intact.