You know, I've never tried. We may have to ask someone with more experience. I don't remember it being super runny, but idk........
Edit:
On further investigation the flowable self leveling seam sealers may not be that great for the more vertical areas of the gutters. Gonna consult my local paint store to get the right sealers
for the job. I like the idea of the flowable stuff for the top flat part so it can get down in all the nooks and crannies and seal it. On the A pillar the high solid stuff may be okay since the water runs right off of there.