If it don't leak, don't mess with it.
Don't fix what ain't broke is he saying.
Unless the rivet is leaking, I wouldn't mess with it. Aluminum does not like to be worked cold, and dented aluminum stretches to some degree so anything you do will likely make it worse in some aspect.
If it leaks support the rivet head and drive it tighter from the inside or brush a bit of Gluvit on the rivet on the inside to seal any possible leaks if you must, but Gluvit is only permanent if painted to shield it from UV light. I've had boats before that had dents in the bow, bottom, and sides from hitting logs and debris in the river and never had one leak because of it. A buddy hit a floating log one day at full speed, it nearly inverted the bow and cracked two ribs free of their rivets but it never leaked. He stomped the dent out the next day and kept running it. It outlive him like that.