It depends on what type of Canadian radio. If its a promotional radio from SXM Canada, you won't be able to do it as it will reject it. If not, it should work. No way to know which it is until you try.
If it does not work, you can try to call SXM Canada and have them release the radio id. You can explain the situation and they may do it. If they do, you should be able to activate it. If they don't, then it will not work.
I've seen it go both ways. We've had customers who have had no issues activating a Canadian radio, and others who were told they could not. Sometimes its just an issue of who you get a hold of. But you should be able to activate it, no problem.