I've own both styles,, the later one with a common boss doesn't have the dividers protruding into the plenum as much as the earlier ones is what I remember.
I haven't done any work on the dividers on any of the 400-3 or 440-3 intakes I've used, I did notice the differences though
I'm sure Indy didn't make those changes for no reasons, especially after seeing what Wilson did to Andy late style Indy 400-3 intake