SO first, it needs to be pointed out again for those that don't know, that ANTIQUE is not a separate classification from NR, RES or PROHIB.
It is in effect an ADDITIONAL classification, that exempts certain firearms from the rules that govern firearms more generally.
Antiques are firearms under S 2 of the criminal code, are subject to the S84 definitions in part 3 of the criminal code, and are subject to all of the regulations relating to firearms by default, unless specifically exempted.
Just as there are antique RIFLEs and antique HANDGUNS and antique SHOTGUNS, likewise there are antique NR, antique RESTRICTED, and antique PROHIBITED. Further, you can have antique PROHIBITED RIFLES, antique PROHIBITED SHOTGUNS, and antique PROHIBITED HANDGUNS.
Rifle, shotgun and handgun, for the most part, are mutually exclusive categories, meaning a firearm can not be both a rifle and a handgun. Likewise, with few exceptions NR, RES, and Prohib are mutually exclusive categories. However, type, ie rifle shotgun and handgun, operate independently of classification, and so it is conceivable that a firearm could meet any combination of these labels.
The definition of Antique is contained in S84 (1) of criminal code.
This definition does not reference firearms type or firearms class, and so operates independently of those other terms. Being an antique, contrary to popular belief, does not make a firearm not prohibited. Further, the regulations published last week do not affect the antique definition. What was an antique last month is an antique this month. HOWEVER, the classification of your antique MAY have changed. What was an NR antique last week may now be a prohibited antique.
The special rules for antiques, ie what they are exempted from, are contained at Section 84(3) of the code.
I am not going to post an exhaustive list of what those sections are, you can read the criminal code here.
https://laws-lois.justice.gc.ca/eng/acts/C-46/page-20.html#docCont.
In short, you do not need a license, a registration certificate or any authorization to possess, use, transport or discharge ANY antique firearm.
So even IF your antique was just prescribed to be a prohibited firearm, it is still an antique, you still don't need a license for it, you still don't need to register it, etc.
HOWEVER, S. 84(3.1) of the criminal code states antiques are still subject to 86(2) of the criminal code, and regulations issued under 117(h) fo the firearms act which requires compliance with the regulations for storage, transportation, display, use, etc. So IF your antique just got reclassified to prohibited, then you now need to store, transport and display it in accordance with the regulations for prohibited firearms.
Now while the recent regulations were issued with an amnesty that authorizes you to store, transport or display the firearm in accordance with its previous classification,
this ONLY applies if you are engaged in one of the activities covered under the amnesty. Storage is one of the purposes listed in the amnesty, but ONLY storage for the purposes of complying with the amnesty, IE surrender, deactivation, or return to its lawful owner.
Storage for the purposes of keeping it would not be covered under the amnesty, nor would any transportation for the purpose of use or discharge, and as such any newly prohibited antique would be subject to the regulations for storage transportation and display of prohibited firearms. Lastly, and confusingly, while those storage regulations do specifically mention rules for antiques, as we have already identified, firearms can be both antique AND prohibited, so you would have to follow the regulations for both antiques, and prohibited firearms. Complying with both sets of rules means complying to the higher standard where applicable.
Clear as mud? I hope that answers your question.