Oklahoma was initially established as an Indian Republic for the "five civilized tribes" (Cherokee being one). Then there was the settler land rush and later, oil under what they had left. As a result many became well off compared to the invaders, so much so that to marry one was "marrying up."
There were also schemes to rob them of such land, from cons to murders and one delightful law where a settler can declare a Native mentally insufficient and petition to become their guardian via the courts, thus gaining control of their assests including the oil.
Anyways, mixing was common enough that today many Caucasian Oklahomans are olive toned or rather easily tannable, a legacy of this earlier mixing.
Anecdotal and seemingly implausible, an ex of mine in the early 90s told me her bestie - an illegal who arrived from Sicily when he was 2 - applied to college as a Hispanic in order to qualify for financial aid. "If they can get it, why can't we?" was the excuse. Maybe not being a citizen, pal? I suspect may ex may have also applied for the same the same way (Italian, born here tho), but didn't tell me since it pissed me off exploiting the system like that, and with me being the one that encouraged her most to go to college...
Anyways, the point is, surprise! the 'truth' can be rather adjustable when it comes to saving money.