I had to do the same repair on my mast. I just redrilled the holes in new locations. It's actually kind of a funny, all be it embarrassing story about the first time I ever stepped the mast. I had just bought my boat and my dad, who used to own a Hobie but sold it to help with medical bills as a result of my introduction to the world, and I were going to step the mast. Keep in mind he hadn't done it for 20+ years and I had very little knowledge of Hobie sailing or any sailing for that matter. I laid the mast on the tramp, connecting the mast step link, and he instructed me to begin raising the mast. Forgeting that it is always more than a good idea to connect the shrouds we began the lift. As the mast became almost vertical I heard a little "pop" and told my dad that I couldn't get the mast to stop. "It's falling!" Luckily he and everything else was out of the way and other that the rivets ripping through the bottom of the mast everything was ok. It was a pretty nice introduction to the design of this great boat as well as some good repair experience.
If you can I would just re-rivet and be sure to do a leak test in the unfortunate event you go turtle.
Good luck
James