I would say "yes."
Why? If the game became really popular and your character suddenly had a fan base, you would also have a sudden reputation as "the person who created *blank*." If not, then you would at least have your artwork "out there" for other video game people to see and someone may go "Hey, that kind of artwork would look good in our game/manga." Sure I would be doing a game for free at first, but on the other hand, you may end up being well payed for something else later on.
Putting that aside, the game would also have to appeal to me first before I would volunteer.
Anyway, that's just what went through my mind when I read this.