I used the same bolts as they are not subjected to a high tightening torque. I even made sure the same bolt went back into the same hole. This was not to save money but if there are even slight differences in thread width and pitch it will cut slightly into the Aluminium casting. The idea is to do everything to prevent the thread from stripping.
Recently, VW stripped the sump plug thread in my Golf 1.8T. That cost them a new sump plus labour.