My Great Grandma was 100% Native American...I have Native American on my father's side as well, but back much farther.
If I actually got the correct paperwork I think I might be able to claim URM.... alas my great grandma changed her name to one that would allow her to fit in better, my grandma knew her original name, but she is dead and she never told her kids what her original name was because great grandma wanted it left alone.
According to my tribe which I contacted years ago when I wanted to learn about my ancestors, I need to know her original name. I don't know anything about her, I never met her and I don't have contact with any family members that might have any information.
So I will probably never get that paperwork, oh well. I want it more so to learn about my ancestors than to claim URM. Although that would be a nice bonus