Last week came time to reassemble the components, but a common issue with the Gen-2 license light assembly is that the rubber mounting grommets (arrows) are no longer supple enough to grab and hold it from twisting side-to-side. Tightening the rear mounting bolts won't help, as they bottom on a "step" on the mounting bolts. There's a few ways to address this, but my simple solution is to add an internal or external tooth lock washer to the back side of the light — the washer takes up the void and the teeth mechanically "grab" both the rubber washer and the fender itself. Tighten the bolts and the light assembly is locked in place. Works for me.
(click on an image to enlarge)