I was actually a little surprised to see the state of Roscoe's personal bass when I saw him performing on the Today Show with the Dixie Chicks. He had this bass with him and at first I wasn't sure who the bass player was. But I checked things out and found out that it was in fact Roscoe on bass with them.
The maple fingerboard was never an option on production RB 5 basses. However, it did become an option on the RB IV when it was introduced. And the plastic ramp/thumbrest was never standard, either.
BTW, that's actually a shot of Roscoe playing with Leonard Cohen at the Coachella festival. He was serving as both bass player & music director during his stint with Leonard Cohen.