Steering shaft. Are you calling the shift tube the selector shaft? Either way, the I.D. of the bearing above would be way too small for the shift tube.
The column shift bushings without the roller/ball bearings inside just keep the shift tube in place so it's not loose inside the jacket. It also keeps out road dust to an extent. In addition, there's also usually a foam seal that goes around the shift tube but those disintegrate over time.
That rubber is an isolator for the upper parts of the column where the driver's hands are. It absorbs vibrations transmitted through the steering shaft.
