Continuity mistake: When Kelso flies off the tread mill, banging into the wall and making the book shelf fall on his head, the books falling to the floor change position in the next shot.
Continuity mistake: The second time JD and Turk try to get into the night club we get a shot from behind the bouncer with his arm down. When it cuts to a close-up of the bouncer, he has his arms crossed.
Answer: No, it was a fake, they used a stamp.
It is real.