Mr. Dewey identifies himself as the Vice Principal but in later episodes he is the Algebra teacher. He is never referred to as Vice Principal in any other episodes.
Jessie recommended sending Screech to Disneyworld for his birthday, which is across the country in Orlando Florida, when she could've recommended Disneyland since it's in Los Angeles where they live in.
When Zack is impersonating the school secretary and calling the students into Mr. Belding's office he refers to Screech by his nickname of Screech instead of his actual first name (Samuel) as any actual school staff member would.