Caliper rebuids are very easy. The cylinder does not need to be honed, but it does have to be smooth with no pitting. If it's pitted it has to be replaced. If you can take it out and apart and inspect it before hand it would be best. Then you'll know whether or not it has to be replaced. If it does, the $60 rebuilt sounds pretty good if it is an actual MB part.
1982 Mercedes-Benz 300CD
1982 Mercedes-Benz 240D - stick