No. I helped my buddy put it on his hunting camper roof an it didn't work that well. He got it for free because his company at the time packaged it for resale so he didn't lose any money
I would get a roof sealer designed to adhere to the roof type membrane you have... Also before you apply any sealer, make sure to clean the entire area with vinegar and water.. Personally i would not use Flex Seal for my RV Roof.. Lipert makes some nice products for that purpose.