The box of Eggo waffles that Laverne has is a box design from 1982, not 1966 when the series takes place.
Penny Marshall was born in 1942 and Cindy Williams in 1947. This makes Penny 39 and Cindy 34 at the time this episode was shot. Laverne and Shirley claim to be 28.
This episode features flashbacks to the season-one episode "Falter at the Altar."
The stage for the acrobatic act looks surprisingly like the one used for the many talents shows in Milwaukee!