When customers don't pick up a mount from my shop, after no word for many months.....
eBay sells them pretty quickly.
Never tried to move a large hard to ship item though. But you can list it as local pick up only.
Value is another issue as mounts won't usually sell for the amount it cost to have them mounted.
I would think an elk would go for a good price to the right buyer as long as you can be patient waiting for that person to bid in.