You do not need to remove it from the car!!!
The easiest thing to do, is take the cover off, remove 5th gear, and post some pics. You'll need to remove the nut, knock out the pin holding the selector in place and then remove the gear/hub/synchro etc.
You may only need to deglaze the synchro, or you it could be the engagement teeth on the gear. If the hub is damaged/worn, you can run the 5th gear one the opposite way, to save some $$$. It all comes down to how much of it is in need of repair.
If its just the deglazing, its a simple repair, and cheap. If it requires 5th gear, etc, it adds up.