I had a flat the other day, actually the rubber on the inner sidewall was breaking up so bad that as soon as I put air in it, it would go flat in 10 minutes. I tried to put on the spare, actually I had to call AAA because the car didn't have a jack and I was 100 miles from home, and when you put the wheel against the rotor, the wheel bolts were too short and it couldn't be mounted. Looking closer at the wheel I see the face is a bit dome shaped while the wheels on the car are flat. Anyway, I had to call AAA again to tow the car to a shop and swapped the tire on the spare with the regular wheel on the car. The part number on the spare is 124 401 18 02
and it's the machine finish while the wheels on the car are silver. Did the previous owner put in a wrong spare or do they need longer bolts?