The first scene in an old west town references Gunsmoke (1955). With this episode, its 636th, The Simpsons (1989) surpasses the old record of 635 episodes of a scripted series held by Gunsmoke (1955).
There is a scene in which a hubcap from a wrecked car rolls by, Abe yells at it, and it goes away. A similar gag was used in the season thirteen episode "The Old Man and the Key." In both cases, it was Homer's car that had been wrecked.