Yeah, I think the airbag equipped models are the ones with the big knee bolsters... my '88 300SEL has the big bolster.

About the dash cover - I wish I knew. It was on there when I bought the car and I loved it. I would love to have one for my W126. It only had two cracks in it and I am sure it was put on because of that. If the old lady whom I bought the car from still lives there I would like to ask her. She was moving though, which is why she was selling her deceased husbands car. I regret selling it, but I needed a larger car. I loved the diesel engine though.

The guy that bought it lives in Asheville and said he visited this site from time to time, but I have not seen him here... hopefully the car is still giving him good service. I feel that with care that car would have easily gone 400K miles before major repairs. I really do.