There's a little gap at the bottom left and if I tug on the trim, it's loose and hollow. I can hear road noise coming in from behind it.
I just wanted to check if it's safe to caulk here before I fill that gap with a strip of foam, then caulk it off. Ie if there's any purpose to the trim being loose that I'm unaware of.
Edit: this is the interior.
I'd try clear silicone. Very easy to work with, won't stain, and pretty easy to peel off if you need to. Won't hurt, will probably help.