The crank big end bearings are not really expensive. I'm not going to look it up but I have seen a couple little pieces of rubber cost more. Not uncommon for there to be a little scoring. Check for grooves in the corresponding place of the crank. I have put car motors together with a little scoring in the crank but these were fleet vehicles. On an Airhead I might want to find a better crank if it looks bad. But I also would probably use a crank that had a couple small scratches.
I have mostly heard bad stories about regrinding Airhead cranks. Not only is the radius in the edges critical but the hardening of the metal is not easy to do. Some of the best say to get another crank. And here's the thing, any where in the World right now for any Airhead vintage engine needed an extra, spare, used crank can be found. They are cheap. Maybe in 50 years it will be a different story