I think it comes down to the manufacturing technique. Machine to shape and then harden (accepting that the machined shape will deviate slightly with the hardening process) or machine, harden, then finish grind to a precise shape. Option one is lower cost and more common and option 2 is how you will see that Campagnolo and the other the higher end parts are made. Look for the ground surface in the bearing race area in contrast to the balance of the part regardless of the plating, etc.