Presumption as to documents: prosecution tendered or seized documents presumed genuine unless contrary proof, enabling admissibility. Where a document produced by a person or seized from their custody and tendered by the prosecution is offered in evidence, the Court shall, unless the contrary is proved by that person, presume the truth of the contents and that signatures or parts purported to be in a particular person's handwriting are in that person's handwriting, including execution or attestation as purported; such documents shall be admitted in evidence even if not duly stamped, provided they are otherwise admissible.