When your Field Skillet arrives, fresh out of the box, it's ready to cook with. We recommend giving it a quick rinse and drying it in case any dirt or debris gets on it during shipping. But as for seasoning, an extra layer is not required before you start your first cook.
With that said, cast iron gets better with use. True nonstick performance develops over time, as you build up many thin layers of seasoning from everyday cooking. So while your pan is ready to cook fresh out of the box, it's not the best version of itself. In fact, it will only get better, and more seasoned, each time you use it.