Paper Work - S6-E11
Revealing mistake: At the start of the episode, when the camera zooms in on the words 'Los Angeles County Fire Station 51' which are attached to the side of the building, we can see that this shot is actually played in reverse - notice the cars/trucks behind the station are driving backwards. Additionally, note that the real 127's rig is seen in the driveway to the right. Also interesting to notice are the upper/lower metal bars which are attached to the bricks, where we can see the bars are much longer after 'Station 51', with a space for something missing, due to the fact that is was made to hold '127' on it.