One of the very rare gadgets is the shift boot and gear knob in “Rau Leder” from BMW with part number 9068413 and the associated gear knob also in “Rau Leder”, which could still be ordered from BMW until 2008. In the current parts catalogue, as of March 2023, this is no longer to be found in the parts catalogue. You can only find it if you search directly for it by entering the part number directly in the ETK (electronic parts catalogue) by specifying the part number.
BMW no longer lists many parts, especially the accessories and retrofit parts in the newer versions in the ETK, since these parts can no longer be ordered because they are no longer available.
We recently bought a BMW E36 that had such a shift boot and knob installed. Since we are restoring this vehicle to the factory delivery condition, we have removed all parts that were not installed in the vehicle from the factory and stored these parts in our BMW parts collection.
Here are the pictures of the shift boot and shift knob in rough leather: