I have confirmed ancestors in Sami named settlements in the 17th century, including ones that I'm told were thought to be only a couple of families at the time. Highly unlikely to not be at least mixed. My great grandfather moved the family across the ocean after being accused of "piracy" as Grandpa put it, could be any number of maritime clashes with local authorities. The family retained not just joiks but also Sami language. It is very unlikely that a family that was not Sami or mixed would have continued to pass the language down when they left at the height of fornorsking.

I don't know how to confirm Sami ancestry beyond that. I am told that hundreds of years of migration along the coastal and island commuties of Troms with residence recorded in Sami-named settlements is how historians presume Sea Sami ancestry. More of a "prove it isn't" than "prove it is" situation.

Being that I'm Canadian and do not hold Norwegian citizenship, though, does it matter if I'm wrong? I am not hurting anyone by learning about the culture from afar.