If the flange was where it was designed to be, you could remove the bolts easily...it is designed to be installed on TOP of the FINISHED floor. Those slots are stronger than the long ones, so they are the preferred location, but the all-plastic flange is not a favorite. The rough edge is because that flange came with a knock-out plug so it could be installed and not leak sewer gases while the room was finished. It is designed to be broken out when ready to install the toilet at the end of room prep. You can take a rasp or some rough sandpaper and smooth them over if you wish, but normally, since the toilet's outlet is centered on the flange and is smaller, they have no effect.