I'm changing the clutch, rebuilding the midlands, and replacing everything that had to come out - should i resurface the flywheel? I don't think it even has worn the original surface off of it...Does any one know what the specs for the flywheel are?

 

You'll prob be just fine to reuse it as is. I think I've only ever had to replace one flywheel on an R50 yet. They are pretty durable.
http://www.waymotorworks.com/flywhee...per-non-s.html

 

Clean it up with brake cleaner and scotch bright. Looks like it's in really good shape.

 

Your fly wheel looks good; how many miles do you have on your Mini?