Plothole in The Slicer
In the 1997 Episode "The Slicer" George has that whole ordeal where he tries to airbrush himself out of his bosses picture.
George explains it happened in the Summer of 1989 but he has a full head of hair still in the picture. The pilot took place in 1989 and George was just as bald then as he was in 1997.
Also "The Finale" confirms "The Pilot" was canon with the final scene