Both a revealing mistake and an anachronism, when Kevin is driving with his drivers ed. class, and with his dad, an 80s station wagon and an early 90s Chevy pick up can be seen in the background of their respective scenes.
While Kevin and Jack are discussing a trip to pick up shower doors, a crew member's reflection can be seen in the window between Jack and Kevin. Also, as Kevin is walking to his position, a crew member is briefly visible in the first window he passes.