During season three, Joey has a San Francisco Giants pennant in his room. This was done to mirror the real life San Francisco Giants going to the World Series that year and was also broadcast on ABC. Later in the season and in the series, that same Pennant would be displayed in the girl's room (and later DJ's room), while Joey had a Detroit Tigers pennant in his room for the remainder of the series.
Your sister is such a tattle-tale.
Steph: I am not and I'm telling you said that.
During the final season, a door is added in the kitchen directly from the hard camera. In the series revamp "Fuller House" the extra door is now gone as the kitchen is much darker than it was in the original.
A longer version of the theme song was used in the first few seasons of the show but was truncated in later reruns, though this version was kept on some episodes, such as the pilot when it airs on ABC Family. First season episodes in syndication also feature a credit for Mary-Kate and Ashley Olsen (they were only credited during the end credits in the first season).