Jimmy G hasn't passed much because he hasn't had to. His few throws in both games came on their early scoring drives or the few times they had bad field postion. After they had leads the offenses they faced were inept and turned the ball over. With short fields and strong leads for most of both games, they didn't have to do more than run out the clock on offense.
Unless KC struggles against the SF defense (unlikely), Garapollo will have to have a game like he did against us.