Not necessarily. Many convection ovens channel the air from the bottom to the top, meaning that the hot air makes contact with the bottom of the loaf first. To prevent this, you need to turn off the convection function of your oven for sourdough bread baking. It may be more energy efficient for some foods, however, for sourdough, it can be a problem. If you wish to continue to use convection heating, you'll need to use a heat insulator (like a baking sheet) to reduce the effect of the bottom to top airflow.