Can you post any pictures of the teeth on the gears for us to look at? That would make it easier to help you in the decision of whether or not to re-use these gears, or go find another set. Based on my experience with diff bearings letting go, I have found it better to simply replace the assembly, rather than clean up the damaged gears, install new bearings and let it rip. I have never had good results in this area. Others may have had better luck on the rebuild and reuse side, though.