I haven't replaced the leather trim handle but I recently replaced the entire hand brake. I broke the original in half. Basically the hand brake is plastic and the leather wrap is glued. I broke the hand brake in the middle right where the leather seam sits. Hope that makes sense. In my humble opinion you can re wrap it but it appears to be challenging considering how well the leather is glued. If you pull hard enough half of the hand brake should slide off. I don't recommend it in case you break it
Everything underneath the leather is plastic. Only the handbrake gears are metal.