Ah. A couple things I forgot.
1. You'll want to use Notepad ++ to edit XMLs (if you aren't already). That way you can easily search for entries, make changes and keep formating. Normal notepad will screw this all up.
2. If you use Genres and/or individual Manufacturer Wheels those XMLs will also need to be updated. So for example you unclone a beat-em-up in the main MAME.xml, now you also need to unclone (or copy paste the fixed entry) into the Beat-Em-Up genre xml too. And if it was a Technos game and you have a Technos wheel it needs to be done there in both spots as well.
3. Rocketlauncher shares artwork from parent to clones, but now that a game is un-cloned you may need to copy/paste and rename the artwork/media for the game. So for the above game you may need to make renamed copies of: Theme, wheel art, video snap, bezels etc...