The most accurate way to test to see if the buns are fully baked is to check the temperature of the dough by inserting a kitchen thermometer into the center of the rolls. Cooked dough should reach an internal temperature of 180-200°F/82-93°C. If you don't have a thermometer, the tops of the buns should be browned on top and a toothpick inserted into the middle (go in at an angle between the folds of a roll) comes out clean.