My wife was born and raised on the Crow Agency in Montana and refuses to put down race on any form (as do our kids). The amount of white people pretending to be American Indian has gotten ridiculous.
But with the Five Civilized Tribes it's usually true even when the claimant doesn't know it.
I had a friend in high school who was one quarter Choctaw and his Grandfather had been the Choctaw Sheriff in Broken Bow, OK. His mother was a "Louisiana Creole" which only meant she could tan easily every summer. He married a classmate of ours who's family came from the old world India, but they were and are both devout Presbyterians. Their slightly darker skin came from a few different directions.
My wife had a relative on the Dawes Rolls but when I finally looked her up it said she was one eighth and the Dawes Rolls were compiled three or four generations ago. But that was a factor in my wife being drop dead gorgeous.