We can confirm that the JCW/GP lug bolts are different from the standard MINI lug bolts. The JCW/GP bolt (pictured on the left in the image) is a finer thread/pitch and also has a larger thread/shaft diameter. The JCW/GP bolt is also slightly shorter than that of the stock MINI lug bolt on the right. The taper toward the head of the JCW/GP bolt also appears to flare out at less of an angle than stock however a standard 17 MM socket fits both for rotating and changing tires.
We can’t confirm but have been told that all cars with factory JCW brakes built since June ’06 are like this. We also can’t immediately say what this means to after market wheel options on the JCW/GP but we can only guess that they will most likely be limited due to the non-standard bolts.