Said plat shall be signed and acknowledged by the mayor, who shall also certify that he or she executed the same by reason of the failure of the owners or proprietors named to execute and file the same; and such plat, when so acknowledged and recorded, shall have the same effect for all purposes as if executed and recorded by the proprietors or owners themselves. All recitals and statements in such plat, certificate or acknowledgment shall be prima facie evidence of the truth thereof.