Yes and no. When you get there, there will be cards to fill out. It's less of a reservation and more for tracking. It is first come first serve, but I have camped there many times and have never seen it close to being full.

No reservations this site was first come first serve and self registration.

No reservations are not needed you need to fill out a registration form when you get there

Reservations aren’t needed but it’s first come, first served

No, sites are first come, first served