Yeah, and that's the whole point of it. There's too many applications of AR for Apple to build alone.
What will happen is a developer will build the app I mentioned above (could exist already) and then Apple will later build it into the camera app. I've never seen an app maker build functionality into any of the iPhone built in apps.
What you _can_ do, (and it's quite easy), is to create your own app, capturing video from the camera. Then you can overlay any AR content you wish onto it.