Yes. If the Liberal Party takes out an ad saying “we're wonderful”, paid for by them, as you well know, or if a registered third party advertiser takes out an ad on the radio, they, too, have to identify themselves. The traditional media, from my understanding—I could be wrong—have to keep a repository of the those ads, which can be then sought back.
The effects of these things are not always identified by voters immediately. If they think there is a problem or something suspicious, it's often even after the election has happened, and you have to be able to go back to this.
I don't believe any of these sections creates such a repository, but I think it is coming.