The actress playing the character of "Muffy" was also in the season 2 episode "Tux for Two" where she played another snobby rich lady named Margaret. Coincidentally, in this same episode actor Frank Birney who played who played a waiter in the "Tux for Two" episode, plays a party guest in this same episode.
When pressed by Larry about whether Balki knows any rich people, Balki eventually agrees he does not. But in Episode 3x20 "You Gotta Have Friends", it was co firmed that Balki had met, and become fast friends with Carl Lewis. If not necessarily very rich at the time, he was certainly extremely famous, and rather well to do.