Can't really flip them, the clamp bolts are counter sunk. You also need a steering system, like a UMI bearing setup. The SJ plates are made with the correct machined surfaces to fit the orings on these sytems, so you can't just flip a SJ plate. The stock SJ plate won't work cause it's a bushing system. One could get really creative and make a bracket for a stock SJ system on the cheap so the pivot ball mounts to the other side.
The stock SXR turn plate has is mounted on the bottom, so if you mount it on the top, you are basically flipping it, putting the steering on the right again.
Blowsion's Kommand turn plate is made so that you can move the little arm from one side to the other for this very reason.
Cold Fusion has a really nice fat bar setup for the SJ, but he didn't make it so it has steering pivot setup on both sides (which is probably a $10 production change), or else I'd probably be getting one of those. They are setup to use stock SJ bushing mounting systems. (you listening Carl?)