When Maureen writes on the chalkboard at The Iron Horse restaurant, at first the board says "Pan Fried ass", but when the camera zooms in on the board in the next shot, it reads "Pan fried Butt".
Congress passed the National Minimum Drinking Age Act in 1984. Teens didn't need fake IDs to drink in 1980.
Michigan, where the show is set changed the drinking age to 21 in 1978. Two years before the time the show is set.
Howie Gelfand remarks to Nick "Sorry, Bill Laimbeer" (referring to his height). Laimbeer didn't become a Detroit Piston until February 16th, 1982. At the time that this episode would have taken place, (1980), Laimbeer probably would have had little relevance to Detroit-area youths.
In Millie's cousin's house there's a poster on the wall of Pink Floyd: The Wall (1982) which wasn't released until 1982. In an earlier episode, Nick mentions seeing the film as well. So this makes two times "The Wall" film is out of sync.
Mr. Rosso is seen playing a Yamaha DX-7 digital synthesizer, which was first released in 1984. As often seen in early 1980s MTV music videos, the manufacturer's name has been painted over, to avoid copyright infringement.
As he accosted Vicki for reportedly disliking Three's Company, Eli began to explain why Mr. Roper didn't want Jack Tripper living with two women. However, Mr. Furley had not been the trio's landlord for over a full season by this point. Norman Fell and Audra Lindley left the series in the spring of 1978 for the spin-off The Ropers.