Swing Arm

After passing through the galleries created by the St. Louis Science Center for the tour, one passed through a swing arm (apparently at the aft end of the S-IC Saturn V first stage) to enter the Smithsonian portion of the the exhibit.

I suspect that this is not part of a real swing arm but rather created for the exhibit; there's no bottom to it, for example. However, it does have a fairly convincing pivot hinge, so I'm uncertain.