ACME vs American/Stehl - turning explanations needed

If I'm understanding correctly, on swivel type dollies......
the wheel pan assembly which runs from one fender to the other is what is stationary and the tongue underneath swivels left/right as tow vehicle makes its turns.

If this is correct, is the center bolt in the image below, the pivot point? If so, is this one bolt what keeps everything together? If so, that is a lot of accountability for one bolt. That bolt breaks and disaster would strike, correct?

Image is of an American Car Dolly