The hex bolt is the pivot for the front swings, and, if I remember correctly, it doesn't come off. It has nothing to do with attaching the front hardware to the front extension. The hardware is attached with wood screws (underneath when the swing is moved all the way left or right). At any rate, the rivets should be tight. Check to see if the play you get isn't just the metal of the front hardware twisting a bit on the knurled tighteners for the front swing as you push the standard (tightened on the lens axis) forward and back. If that's it, you can move them a bit (the knurled swing tightening knobs) to make it more stable. I agree that you should shoot it first to see if there's a problem. If it's bad, check with Ken Hough on options. He has a lot of hardware.