T-Rex does take reservations, but you may not need them. When we went last year, we walked up and got a table, and I think that was before they started taking ADRs. For our most recent trip this past April, I made an ADR, but we got there earlier than the ADR was for and we were able to get seated as walkups. They didn't even check our ADR, so when they seated us, they didn't even know we had reservations. It was as if we were just random walk-ins.