sealing roof seams

[Bazupe]

I have a Starcraft RT13 tent trailer. I am in the middle of rebuilding the roof/lid due to water damage. I only have seams that run down the edges of my trailer, (no middle seam). My question is when I reseal the seams on the edges do I need to remove the metal trim and then put down new sealant and reinstall the metal trim or can i just clean up the old sealant from around the trim and reseal it that way? i am going to put a couple coats of the DIcor Fiberglass coating on the whole roof when I'm done.

Anybody have any other advice as i try to rebuild and reseal the roof so i don't have any more leaks.

Thank you