The wall between the garage and he house has to be fire rated, typically 5/8 type-x drywall and a fire-rated door. Intended if a fire starts in the garage, the spread to the house will be delayed by a certain time, allowing the occupants to evacuate. The door should also have an auto-closer and a seal around the edge
So if you had pulled a permit, the plans would only have been approved if such things were included. Also, the inspector would have checked such before closing the permit. Hence everyone's recommendation above that permits are good things, not just a tax grab.
i'm just an amature though, there may be other reqts in the OBC that a professional would be aware of...