No, they are all first-come.

The campgrounds in this area have changed from REcreation Land to the State Park system I believe. But this is what I found on the linked website for Sawmill: Jesse Owens offers four no-fee campgrounds. Campers should follow the self-registration process. Campsites may be occupied on a first-come, first-served basis with a two-week maximum stay. All other state park camping rules apply.

No, sorry, there is no way to reserve a campsite ahead of time. There are 27 sites available, including a 25A and 25B. The registration box is located at the bathroom. Half the registration goes in the reg. box, and the other half goes on the white pole in front of your campsite.