Well I've had my instrument cluster in and out several times and it's never needed to be coded. Can't see why it would.
I vaguely have something in my mind that says it's one of the components/modules that stores mileage and you should not drive with it disconnected or you create a mileage error (I stand to be corrected on this as I usually have the cluster out to mess with LCM's that also influence mileage readings)