Presumption as to documents: handwriting, execution, admissibility, and truth of contents are presumed unless disproved. Where a document is produced by or seized from a person under the Act or received from abroad in an investigation and tendered by the prosecution, the court shall, unless contrary is proved, presume the signature and handwriting to be that of the person it purports to be, and in executed or attested documents presume proper execution or attestation; admit the document despite defective stamping if otherwise admissible; and, for domestically produced or seized documents, presume the truth of their contents. 'Document' includes inventories, photographs and certified lists.