Good question... I have no idea. I have seen pictures of other people's ktm's torn down and noticed similar corrosion on the rear bolts as well
I will clean them up but I am not going to replace them.
Was able to remove the old seals and bearings for the crank and replace them with new ones. I had to heat the case halves to about 150 degrees with a propane torch.. after that, the original bearings fell out. I then took the new bearings which were in the freezer overnight and they dropped right into place
Cranks comes back today.. I should have the bottom back together tonight.