Marking your rolls with a marker will not generally help. Normally if a bank sells coin they have to dump the coin into a huge bag to sell so that it can be counted with a coin counter. So if you mark them chances are the wrapper will not be the same one in the end.
If you are dumping coin I would say dump at a different bank than the one your buying from. Normally a bank will use the same company to buy and sell money from. So even if you are going across town but with in the same bank you run the chance of gettin the same coin back. But here again before banks can sell coin they have to put them into a big bag all mixed together so all the rolls will get mixed together so the rolls wont be the same as when you took them to the bank.