Any deed or deeds which have been heretofore, or shall hereafter be executed by the commissioners of any county, in pursuance of the act of twenty-ninth of March, 1824,¹ but which shall not have been acknowledged before a justice of the peace before delivery, shall upon proof of the execution thereof by the subscribing witness or witnesses thereto, as in case of ordinary deeds, be held to be as good and valid, for the purposes of record, as though such deed had been regularly acknowledged before delivery.