If the old sealant is tight and not cracked, why do you need to reseal the RV? If it is dry, brittle, cracked or losing its seal, then it must be removed.
I also have a comment on Geocel Proflex. I used it successfully once but had issues the next two times I tried. I got tubes from a hardware store and after a great deal of effort, I found the sealant did not adhere well and I had leaks and sealant peeling off. I got new tubes from Camping World and repeated the process with the same results. In both cases, the material seemed thicker than the first time I had used it. Maybe I got old tubes of material or there was a QC issue. In any case I now use Dicor and will not try Geocel again.