If I only had a nickel for every rivet I've tightened or replaced in Lowe's and Lund's in my life........
It's never a matter of "will they leak" it's how much they will leak. A riveted boat with a elevated floor and a auto bilge might never appear to have rivet seeps.....but they do...
Just put your non-leaking riveted boat on the trailer and fill it with about 6 inches of water and tell me what you see.