Have you put the cap on to confirm?
Look at your old wheel,the part that attaches the center cap to the wheel looks like a cup and attaches to the cap with 1 screw at the bottom so the inside of the cap has plenty of room for the dust cap that is sticking out,I thought the same thing when I put my wheel on without the cap,once you take the cap off your old wheel you will see what I am talking about.