No matter how it comes off there is one very basic concept here. WHEN you can purchase a part separately from LR... guess what, it can be replaced. If this simple knob were not meant to be replaced or was not trim specific then it would not be a separate item. If it were a part of the armrest assembly it would require separate part numbers for each level of trim in each interior colour and each grade of leather in those colours. Even LR is not that completely moronic.
Height knobs are a separate part number in microcat. They can be ordered separately. Thus they can be changed across trim levels.
Have I ever done so? oh heck no, I am not that retentive that a knob excites me. However if someone want to change from boring black to nicely ribbed for her pleasure, stainless trimmed.... go for it. If the old one does not twist or pull off if warmed up, then cut it off and you will immediately see how to press on the new one or spin it on.