While the management of each pack is left almost entirely up to the pack leaders, in general, yes. If they have two wolves who are both excellent hunters, there is nothing at all stopping them from having several "Hunters" in their pack. However, they have a right to refuse your request for a certain role, or find you more fitting for another, based on what skills your wolf has shown. Not being of a specific pack role, for example a "Hunter", does not mean that you cannot hunt anyway, as for a pack to function all wolves are required to do a bit of this and that at all times. However, a wolf ranked "Hunter" may take on a leading role in larger hunts, or train other wolves. The title is more of an acknowledgment than anything else.

The best way for you to find this out is by sending your pack's leader/s a friendly PM and inquiring about it — there is no harm in asking after all! In order to earn a role, you must have completed five threads demonstrating or practicing that role (please see the Life Points guide for details).

Concerning life points, your wolf does not need to hold the rank in order to demonstrate it. However, you must hold the rank in order to be able to teach someone else.