You can dress them with a simple flat file, raker files do a decent job. I use a round scotch brite abraisive pad on my die grinder, I've found that to be the best for knocking down burrs. If the rails need a more serious treatment a round stone on die grinder at 90° gets them flat. You should not feel any burrs on edges and a bar should be able to stand up on its side on a flat surface and not fall over. Even sandpaper can be used if resources are limited. Learn to do it as its basic chainsaw maintenence, driving to a dealer to dress a bar is well a little bit silly.