(1) A document which purports to be signed by a person authorized by the Commissioner and to certify that an air rifle, air gun or air pistol specified therein was-
(a) at a time or times specified therein tested as to the muzzle energy with which a shot, bullet or other missile could be discharged therefrom; and
(b) found at the said time or times to be able to discharge the shot, bullet or other missile specified therein from the said air rifle, air gun or air pistol with a muzzle energy measuring the number of joules specified therein,
shall be admissible in evidence in any proceedings for an offence under this Part on its production before the court without further proof.
(2) On the production of a document under subsection (1)-
(a) the court before which the document is produced shall, until the contrary is proved, presume that-
(i) the signature to the document is genuine;
(ii) the person who signed it was duly authorized to sign at the time he signed it; and
(b) such document shall be prima facie evidence of the matters contained therein.