That slot on the Center Cap is suppose to align with the notch on the wheel so that proper clearance is provided for a small pry bar (most use a small screw driver) to remove the center cap w/o incurring any significant damage to the wheel or center cap (I've got a set of small plastic pry bars in the trunk so as not to do any damage to the wheel or center cap). And that notch on the wheel is always directly opposite the tire valve stem. I can always tell when a Seller (Private or Dealer) isn't aware of this when that opening with the Center Cap isn't directly opposite the valve stem. I'm not saying that the Center cap can't be installed in any orientation on the wheel, but the Factory did try to make it easy to see where the Center Cap was supposed to go when pressing it back on the wheel (M60A3Driver shows this in his post on replacing the wheel logos). Note: One also sees that the grooves on the wheel spokes align with the notches on the Center Cap when the cap is properly aligned.) Makes for a much better looking wheel when everything is like it's supposed to be! IMO