If you ever want to get ownership of a specific file in the future, you don't have to change the general settings. You can just do it for that particular file. How to Add “Take Ownership” to the Right-Click Menu in Windows Explorer
If I remember right, once you have this option in the context menu, you can also use it to restore default ownership. Maybe this will work for you. It's not clear to me exactly what you did and how you did it.