http://www.rifftrax.com/night-of-the-living-dead-0
Found it, but I don't think it has a DVD release, so it would just be an audio commentary without an image. So yeah, it would have to be manually synced up. I've never heard the trio commentary, so I can't speak to if it is worth the effort or not, but they are usually pretty hilarious together.
Looking forward to the release, either way! The cover looks great.