They all have to meet a certain spec so however they do it is on them apparently one has a little deep dimple while the other has a lesser deep dimple but kind of a cutout on the other side. Between these two no it's not going to matter at all.. this is kind of like .."which turd is the shiniest".
If you're even considering flow increases by Valve change ...you should really buy a good valve instead of buying replacement stuff.
Hope that helps somebody.