As someone who knows a thing or two about Polish history, was born in Poland, whose entire family is Polish and can trace their ancestry all the way back to when Poland first became Christian then later officially became the Kingdom of Poland, I can say unequivocally that Poland has always been "super white".
The whole idea of 'whiteness' is a product of colonialism and it applies poorly to a place like Poland.
There were better ways of tracking ethnic identity than skin color.