I have a 2001 SLK230 that I purchased new. Yes, the paint bubbling on the valve cover and and the red Kompressor markings are normal. It bummed me out when it happened
, especially since I keep it wiped cleaned and waxed. Hey, I got over it.
I plan on removing and re-painting them in the near future.
You didn't mention how much for the '99, but I bet you could find a 2001 with less mileage for about the same money.
I agree with the pre-inspection...money well spent.
Good luck,
Dave