Harry calls Walter "meathead" because when he walked in the door, Lucy had just plopped a package of ground round on his head. "Meathead" was also what Archie Bunker frequently called his son-in-law Mike Stivic on "All in the Family," a show that began airing on CBS in 1971.
Mary Jane says that she's been going to charm school. In 1954 Lucy Ricardo and Ethel Mertz attended Phoebee Emerson's Charm School to get their husbands to pay attention to them at parties.