I assumed that since the bolts are designed to stretch when first installed, they should be replaced. I suppose if they are within spec then it doesn't matter. Perhaps one of the techs can elaborate.
I love my 300E although mine is pretty tired, ~250,000 miles of which I've contributed the last 70,000. I bought it 4.5 years ago on a whim. I was looking for a 16V and stumbled upon it. I decided to buy it because I knew how rare they were. In it's previous life it wasn't taken care of, I believe early on it was in an accident and repaired. It's far from perfect but it's still serviceable. My dream goal is to find a really nice 'regular' 300E with all the options I want and then swap trannies.
Anyway, good luck and let us know how your repairs go.