Still a ways off needing it yet, but when I pulled the front and rear guards off the brown beast, either side of the plastic beading was coated with the factory grey sealant. The stuff has roughly the consistency of Blu-Tac - stays flexy, medium adhesion, seals moisture out of the panel join but still lets you pull the panels apart. What's it called, who makes it, who stocks it? Cheers as always...

Should not be any sealer there

It's probably Mastic.