Temporarily place it on the bed, (masking tape),put a flashlight in the bed, shut the tailgate and and look at the gap. it will do absolutely nothing to seal it there . It's not what I think, It's what I know. nothing is 100% but we are talking about a Maverick, right?
That’s the size of mine. Glad you found it. That kit from Cabela’s above looks pretty good too. I see it has the 3m tape but to be honest weatherstrip glue from 3m would work great on the one from Steele.