There shall be printed at the head of a fire insurance policy the name of the insurer or insurers issuing the policy, the location of the home office of the insurer or insurers, and a statement whether the insurer or insurers are stock or mutual corporations; and there may be added to the policy any device or devices that the insurer or insurers issuing the policy shall desire; provided, that any company organized under special charter provisions may indicate this upon its policy and may add a statement of the plan under which it operates in this state.