If it is only the "leather", you could try to find a piece of blackened leather (real), cut into shape and sew it together?
My Golf 4 had a thick leather gaiter on the gear lever. I used to leatherwax it now and then.
Now, the Cali has a very thin "leather?" gaiter with a plastic knob. There is one tiny pinch in the gaiter from sticking the lever in reverse, and thus cutting a hole in the gaiter.
You can take the whole thing apart, but you can't buy the single parts alone. So making one yourself might be the best option if you want it to have a real thick leather gaiter.