Canadian or US version?

[Equisilus]

This has been a question I've been meaning to ask for a while. How does one tell if they've purchased a Canadian or US release of a BD (I'm in Canada)? I can tell, usually, if a movie has been released in one country and not the other, but when they are released simultaneously, and are listed on this site in both US and Canadian versions, do I assume that I have the Canadian one or is it possible that I have a US version?

It's not that it matters, but since a distinction is being made on the site, I'd like to make the same distinction in my movie list. Recently I added the Fantastic Four movies to my list only to discover that the Canadian versions hadn't even been released yet (so I obviously had the US versions, although they appear to be exactly the same). I left the ones in my list as Canadian all the same rather than switch them to what I must have had. I just picked up the Hellboy movies, though, and am wondering if I made the right choice in adding the Canadian versions. Could I go with whether they have a Canadian rating on them?

Of course, I suspect it's a question that has been answered, but my search-fu on this site doesn't seem to be working well; feel free to direct me to the answer if one is available.