Thanks for the tip, Catso. I have silicone. I'll check the gasket/seal situation out. The tail lights have always had fog in the lenses. I thought it was coming from elsewhere. I sealed a couple of tight cracks in lenses with super glue, to no avail. There is less fog now than ever before. I started with a new trunk deck gasket (not an easy or cheap thing to do, $175 for the gasket, getting the old one off was the worst part). I am sure the rear glass was leaking. You don't want to know what that cost. I always supect the ancient moon roof and drains, always. I am just grateful the moon roof works reliably.
Cars, ya gotta love 'em.