You should be OK to drill and tap (CAREFULLY) to the next size up without compromising the bosses in the case. Mark the drill bit so you don't drill too far, use a bottoming tap and get the exact length bolt for the job, cut one if you have to. Don't over-torque and use red loc-tite. Sorry it fell over
FWIW the EBR's have a 3rd bolt on the kickstand bracket that actually bolts to the stock muffler to triangulate the mount.