The opening scene of the attack on the cavalry was shot in the Bronson Caves in Bronson Canyon, California, which was the location of the climax of The Searchers (1956).
There has been no mention of Burt Reynold's character after he left the show. Until here. Bandits have arrived at Dodge, and are dressed as Calvary soldiers, they take over the blacksmith's shop. Festus makes a statement that Jake Struck wont like it, and that he's the first blacksmith they've had since Comanche left. Which is a reference to Burt Reynold's character, Quint, who Festus always referred to as Comanche, due to his being a half breed.