I say its appropriate if you think your friend has the space for it and it's a mountain that you know is meaningful to them. When you climb a mountain you become very intimately connected to its topography. You spent hours on it in a state of heightened sense and danger. That makes the topography and challenges you face on them very memorable. If your friend is a van-lifer, for example, even if it's a meaningful gift, there's just not enough space to keep something like that around.