I think that they were originally imported to Canada and the US at the same time. We've also had Norinco's & PolyTechs since the 80's~ but they didn't reach the heights of popularity they did in the US because at the same time, we were getting Springfields, Winchesters, H&Rs, and TRWs, for the same (and less money).
It wasn't until real M-14s became restricted, then prohibited, that there was any real interest in Chinese M-14s in Canada. This corresponded to @the same point in time that Chinese M-14s were banned from import to the US.