Hard telling what you will find under that silicone, but, once you start to peel it up it should come off fairly easy. I don't know how the Jr was originally sealed at the seams but I have used Sikaflex-715 self leveling sealer on a number of FGRV's with very good success.
Belly Band refers to the equatorial seam found on most FGRV's such as the Compact-II, Scamp
, 13' Lil'Bigfoot, and most others that are built with an upper and lower shell half.
Trim-Loc is a kind of ribber molding used to hold windows
in place. The Loc part is a strip that inserts after the glass is installed to lock the glass in place. (I think)