National Treasure single disc release?

[Deadster]

Hey guys. I recently bought a used copy of National Treasure on BD here in Canada. It was only later that I recalled that this was a 2 disc release. The one I bought is 1 disc and there's no spot in the case for a second disc. I can't find any information online about a single disc release, can someone fill me in on what's up with my copy? It does say Collector's Edition on the cover. The back of the case doesn't indicate a second disc anywhere.

Thanks.