Hank Patterson plays a hobo in the show; he became famous playing Fred Ziffel in Green Acres (1965).
Barney's room is very different than a few episodes earlier, in The Rehabilitation of Otis (1965). The headboard is polished brass, not painted metal; there's a refrigerator in the corner where a sink was earlier; the nightstand is on the other side of the bed and does not have a phone on it.
The bank robber in this episode also attempted to rob the Mayberry Bank in Season 3, The Bank Job.