Short answer: yes, you can use such a method, but it will need some tweaking. You'll need to do the following:
- Lens distortion correction (Barrel distortion)
- Camera transformation (the tracking engine knows the location of the camera, not the screen)
- FOV calculation (You'll need to know the physical size of the phone to do this)
- Make sure the background is black
A good place to start is to check out the ARCameraShifter.cs script. If you're only targeting iOS devices it will be easier since there are only about 4 physically different iPhone models.
It would be great to have a native interface as well so I would be glad to help out.