To run in the belt in the centre of the sprocket you need the black rear hub, rather than the early silver one. The dimensions are different, or spacers that achieve the same thing. The rear drive sprocket on the early cars did not have an outer guide plate and the belt ran a few mm off the edge of the sprocket. Many cars still run like this with no problems, it's not something that needs urgently rectifying. The design of sprocket will make a difference to the life but not the way it tracks. Early ones are alloy, later steel and some replacements are poly overlays. Alloy ones don't last very long.
