1. The commission shall have an official seal with the words "State Tax Commission" arranged in a circle outside the seal of the state.
2. All process or certificates issued or given by the commission shall be attested by said seal.
3. Copies of the record of the commission certified by the secretary and attested with the seal of the commission shall be received in evidence with a like effect as copies of other public records.
4. The secretary of the commission shall be the custodian of the seal and records and be authorized to affix the seal in all proper cases.