On my C class the OEM pads come with caliper bolts that have a blue Loctite/anti-seize coating on the threads. There is a specified torque rating for these bolts also.
I don't think this is a case of bolts getting stretched as in head bolts only being used once. I think because of the safety issue with something as important as brakes, these caliper bolts are intended to be installed as close to original spec as possible.
On another list a week or so back, an owner related the story of what happened when a repair shop forgot to tighten the caliper bolts properly. Luckily he was able to diagnose a repair in a hotel parking lot, but the resulting brake failure on the road was bad news.