You should contact the CFC-RCMP as it's a grey section of the law.
For myself, I own a Ruger 10/22 with the Krinker Plinker kit on it:
As you can see, the rifle looks like a "AKS-74U Krinkov" and gets a folding stock and 2 barrels.
One short barrel with a ½ x 28 tpi tread at the end of the barrel to fit the Krinkov Muzzlebrake or a fake can.
Also there is a longer barrel that comes with the kit which you can also screw a fake can on it.
When I bought the kit, they included a little 10mm pin with a letter. In that letter it stated that for Canadian Customers, you have to install this pin permanently into the stock (so it stays open) if you want to install the shorter barrel so the firearm can stay Non-Restricted. As for the second barrel (the longer one), you can fold the stock, as even folded it is respecting the legal lenghts for non-restricted.
SO... Back in 2011, I talked with someone at the CFC-RCMP (Miramichi), they told me I have to pin the stock, if I want to install the shorter barrel so it stays non-restricted.
If ever I wanted to have the short barrel
WITH the folding stock working,
I'll have to call them to change the status of the firearm from non-restricted to restricted...
From their Point Of View, even if you're shooting at the shooting club, the minute you install the shorter "restricted" barrel, your rifle becomes restricted and you have to advise the CFC-RCMP.
But my point of view is the same as yours. If you head to the range and change the barrel over there and after, you change it back to his non-restricted status when leaving the shooting range, you should be ok.
It's only if you want to keep your restricted barrel on and leave the range with it, that you have 30 days to notify them:
http://laws-lois.justice.gc.ca/eng/r.../FullText.html