The CCC:
91 (1) Subject to subsection (4), every person commits an offence who possesses a prohibited firearm, a restricted firearm or a non-restricted firearm without being the holder of
(a) a licence under which the person may possess it; and
(b) in the case of a prohibited firearm or a restricted firearm, a registration certificate for it.
...
Exceptions
(4) Subsections (1) and (2) do not apply to
(a) a person who possesses a prohibited firearm, a restricted firearm, a non-restricted firearm, a prohibited weapon, a restricted weapon, a prohibited device or any prohibited ammunition while the person is under the direct and immediate supervision of a person who may lawfully possess it, for the purpose of using it in a manner in which the supervising person may lawfully use it; or
(b) a person who comes into possession of a prohibited firearm, a restricted firearm, a non-restricted firearm, a prohibited weapon, a restricted weapon, a prohibited device or any prohibited ammunition by the operation of law and who, within a reasonable period after acquiring possession of it,
(i) lawfully disposes of it, or
(ii) obtains a licence under which the person may possess it and, in the case of a prohibited firearm or a restricted firearm, a registration certificate for it.
That being said...
Seizure on failure to produce authorization
117.03 (1) Despite section 117.02, a peace officer who finds
(a) a person in possession of a prohibited firearm, a restricted firearm or a non-restricted firearm who fails, on demand, to produce, for inspection by the peace officer, an authorization or a licence under which the person may lawfully possess the firearm and, in the case of a prohibited firearm or a restricted firearm, a registration certificate for it, or
(b) a person in possession of a prohibited weapon, a restricted weapon, a prohibited device or any prohibited ammunition who fails, on demand, to produce, for inspection by the peace officer, an authorization or a licence under which the person may lawfully possess it,
may seize the firearm, prohibited weapon, restricted weapon, prohibited device or prohibited ammunition unless its possession by the person in the circumstances in which it is found is authorized by any provision of this Part, or the person is under the direct and immediate supervision of another person who may lawfully possess it.
My interpretation is you're fine but be prepared for a problem if it does happen to get seized and you don't get the reg cert within 14 days.
FF