In any proceedings for an offence under this Act, evidence that—
(a) a firearm does not have a serial number; or
(b) the serial number of a firearm has been erased, defaced or altered; or
(c) the serial number of a firearm is illegible—
is admissible to establish that the firearm is not registered and, in the absence of evidence to the contrary, is proof of that fact.
Division 2—Longarm licences