We tried getting a campsite at Oh Be Joyful but there’s were signs on all of them that said they were reserved and had specific dates. We understood and the website says “first come, first served”. Can someone explain the disparity???

They're all reservation only on recreation.gov.

I just went there... They didn't use to reserve spots. However, recently they have been reserving some spots, while others are first come. When I was there, I had to wander to find the sites that were still open and not reserved. My friend made our reservation prior, and was only able to reserve one night. It is kind of confusing, but that's all I know!