The Rass'lin' Clampetts - S6-E22
Other mistake: When Granny throws the Boston Strong Girl out of the ring at the end, you can tell that the Boston Strong Girl is jumping to get over the ropes.
Christmas Special 1974 (a.k.a. A Perfect Christmas) - S8-E7
Other mistake: Just after Albert pulls the decorations down, Harold yells as he pricks himself on a nail sticking out of the ladder, however he completely misses the nail.