-- Last Updated: Nov-05-12 10:05 AM EST --
When replacing pop rivets, be sure to acquire tempered rivets, the Hardware store variety is mild aluminum and wears pretty quickly.
A second concern when replacing pop riveted in seat hangers with wooden trusses is that the vinyl rail is not reinforced with an aluminum plate as is the case in many WW canoes. You'll want to use 10-24 flathead SS rather than 1/4 in, and use SS finish washers to spread the downforce from the seat. This may not be enough, and worse, the machine screw heads and washers are a real issue, pulling divots from wooden rails when doing boat over boat rescues and from hands whenever paddling.
Bon chance!