Continuity mistake: When the woman in the tub comes crashing through JD's roof the pieces of wood around her change position between the shots.
Continuity mistake: When Elliot and her new boyfriend are sitting outside in the car Elliot's seat belt change position between the shots.
Continuity mistake: When the girl in the bathtub comes crashing through the ceiling, she has her hands covering her upper chest and no bath bubbles. The next shot there is a great deal of bath bubbles all over her and we cannot see her hands covering her chest. As the guy falls through the ceiling, the bubbles on the woman again disappear and we see her hands.
Answer: No, it was a fake, they used a stamp.
It is real.