§ 208. Official seal. The board shall have an official seal. Its records, proceedings and copies of all papers and documents in its possession and custody may be authenticated in the usual form, under such seal and the signature of any one of the members of the board or such officer or employee of the state board of real property tax services as may be designated by the board, and shall be received in evidence in the same manner and with like effect as deeds regularly acknowledged or proven.