Early vs Late 3v Crank Pulley Differences?

I might just order one of these pulleys to see if it fits. In my reading about the swap from the early to late water pump on small blocks, I only ever see mention of changing the pump, radiator, hoses, and (if you want to be able to see your timing marks) the timing cover and balancer. If changing the pulley isn't needed for the swap, I would think that means they're functionally the same.