Along the same lines as previously said, "used bore" gets iron rings. Fresh bore gets moly.
We don't use "chrome" rings anymore, except in rare cases where heavy equipment NEEDS them, usually diesels operating in relatively clean environements. Not uncommon to see an oil-bath air cleaner on engines designed for chrome rings. No machine shop I know of will put a warranty on a street or race engine using chrome rings, against rings "seating".