I don't think that is is the case unfortunately. I thought that might be the case, but even when I select follow and turn on file updates, it does not add that mod to my favorites list when I refresh it. It looks like the feature is either missing completely from the update, or it's hidden somewhere else. Hoping they bring it back (or explain how to add new favorites with the new layout) since I've found a few new mods, after the site updated, I'd like to keep up with.
This has broken in the past. Curse is notorious for breaking their site right before a major release (WotLK). This time the site is working but the functionality is broken. Not leaving "favorites" to aid in your addon updating may just be another effort to move everyone over to the Twitch client. Some of us will never do that though. Fortunately, WoWInterface still works well.