I remember a couple years ago people were having issues with center caps not fitting on the rears. They would use a dremel to cut out a hole in the backside of the cap and they would fit.There are on! Rear caps don't fit over the axle nut so I have some taller ones on order at no charge from the vendor.
I haven't had any problems with mine, and I'm fairly certain that they sit flush with the center of the wheel as well. Shoot me a PM with your email, and I'll send you some pics tonight.johnnyservice did you have any problems with your BK center caps? Mine sit flush with the center of the wheel.