Depends on where you bought it....
Sometimes, some places will sell the rotoflex by itself. Other places sell the rotoflex and bushing together as a kit. I've seen some that sell the rotoflex, the bushing, and new bolts and nuts for the install.
On the wife's Disco, the rotoflex had aged and was soft, the bushing was still intact, so I didn't install it but put it into my spares box. However, don't take that to mean that I recommend not changing it. On some Discos that I've worked on, the rotoflex wasn't really that old, but the bushing had worn and was loose, and 'may' have been what caused the rotoflex to prematurely wear. I'd actually suggest changing the bushing, actually, if it comes with it. But, if not, at least examine the bushing and see what you think yourself.
IMHO, FWIW.....
-L