Gopher often says, "I'm not in the book." This has a double meaning: he's not in the phone book and he is also not in the A.A. Milne book. Gopher is the only Pooh character that did not originate in one of Milne's books. He was originally created to replace Piglet, until they decided to bring Piglet in for Winnie the Pooh and the Blustery Day (1968).
Roo and Gopher pull Eeyore's tail off in the process of trying to pull Pooh out of Rabbit's front door. However, when Eeyore is seen at the honey tree immediately following Pooh's extrication (and subsequently getting stuck again in the honey tree), his tail is back on.
At the beginning of the feature, Pooh's door is seen from the outside opening on a hinge on the right side, while in the Tigger scene, the hinge is also on the right side (which means it has changed sides)
When Rabbit turns in his chair to try to avoid seeing Pooh stuck in his door, he looks in his mirror. At this point, only Pooh in seen in the reflection, and not Rabbit.