765 ILCS 1070/2
That the certificate of the Secretary of State, under his seal of office, or that of any court of record, certified to under the seal of the court, or that of any judge of any court of record (his official character being certified to), of the country or other place, outside of this State, where such conveyance, writing or other instrument shall have been executed, to the purport or effect that according to the usage or law of the land in force at the time (as the case may be), a seal or scroll to the signature of a party so executing the same, was dispensed with or not required for its validity, shall be deemed and taken as prima facie evidence thereof: Provided, that any other legal mode of proving that the seal or scroll to the signature was at the time there, by the usage or law, dispensed with or not required, may be resorted to in any place or court of this State where the question may arise.
765 ILCS 1070/2