I think maybe the reproduction was one of mine. They were EXACT reproductions of the originals. We powder coated them and date stamped them so they would be harder to pawn off as originals.
As for originals, I have personally owned five of them. Two came directly from Pontiac dealerships. One was new old stock and in the original box and never been used. None of them had any bearings in the pipe. They were designed to slip over the mounting pipe.
Maybe the bearing was added buy the previous owner?
Now if you think about it, if you put a bearing inside the pipe at the bottom, you would most likely need another at the top of the pipe to provide stability and prevent wobble. That would also make the mounting pipe much smaller and decrease wind load strength. There really is no reason to use anything but the pipe inside the pipe. Either way they are really cool!