from what i understand a crank workhardens in use which makes it stronger, than when it came out of the factory. (i did do metalugly at college, just the basics though). now this is a desirable thing is it not??. as it's free and no need to pay someone and run the risk of it maybe coming back damaged.
if it does require a regrind i would assume and i hope correctly that this would remove the layer of worl hardening that has built up on the crank.
so as long as it is round and not ovaled at all i would rather try and find shells to suit it.
this is what i have gather as well from reading many articles on supercharging and the odd one on nitrous. one of which was in street machine ad i think all the tech came from the guy mentioned by chip earlier.