What does the current seam look like, if it is a 3 to 4 inch wide tape, it is probably a product called eternabond. If it is, it can be removed by some light heat and scrapping, cleaned and redone with more eternabond. You can find it on-line.
2005 Safari Cheetah 38PDQ - 2009 Ford Flex
Me (Gatogonow), The Boss (DW), Honey Bunny, Maggie May and Mollie Kay (The Gatos)!