The Milner Library at Illinois State University has a collection of Circus Memorabilia, including a nice digital archive. I’ve selected a couple of images that show jeeps Numbers 3, 4, and 5 from the Ringling Barnum Circus.
As you can see below, No 3 is working hard holding up Carmen Barrigon, while No. 4 lazily watches.
http://digital.library.illinoisstate.edu/cdm/singleitem/collection/circus/id/1166/rec/4
Meanwhile, No. 5 is doing all the heavily lifting. The photographer, Sverre O. Braathen, calls this a Ford Jeep, but it looks like a CJ-3A the way the bumper is bolted onto the frame, though it also has a CJ-2A windshield. The rear PTO is raising the platforms for seating. My circus book has a good shot of the PTO setup from the rear, but I haven’t had a chance to scan that.
http://digital.library.illinoisstate.edu/cdm/singleitem/collection/circus/id/2021/rec/1