Aluminess has an "upgrade" kit that I have purchased. It comes with the new bolts, washers and nuts, rubber bumper stops that go near the latch, and a couple pieces that allow the swingarm to "rest" on the bumper when closed.
I am one of those that overload my swingarm that has the bike rack on it.
Dave custom built the swingarm somewhat against his will. I am more cautious when I have it fully loaded with three bikes and other stuff. A long washboard road in a loaded configurations would most likely tear it apart. When they installed it for me, they installed the parts that allow it to rest on the bumper. Without that it would probably already be broken.
Phil