Mo. Rev. Stat. § 490.330: Evidence offered to reject such copy.

Whenever any deed, conveyance or other evidence of title, or a copy thereof, shall be offered in evidence, under the provisions of any of the preceding sections, and objected to, the party objecting may introduce evidence to show that the original is not what it purports to be, or that it was not executed by those in whose name it purports to have been executed, or that the copy offered is not a true copy of the original; and the court shall determine thereon, and admit or reject the instrument, according to the evidence.