It's actually the other way around. The one on the left is the early one and the one on the right is the later version. As I mentioned, you can't really see any difference once they're installed. The brass washers are slightly different too, but so slight as to be meaningless. If you're looking for 100 point show car parts, get the originals. If you don't care about that and want arguably better parts, use the later ones.
