When Annie is comparing brand-name glitter to the cheap kind, she shows a completed banner that says "Welcome Archie" instead of "Welcome MacGuffin Institute"; Archie is not introduced until the next episode, Economics of Marine Biology (2013), where Annie is shown with the same banner that is still being made.
In Abed's footage Chang is seen using a phone in Shirley's store, dialing 555-3190, and Jeff claims they need to find out who is on the other end of that number. When the footage is revisited one scene later, it now shows Chang dialing 555-0190.