This is after the founding of the country. I'm asking about before. Showing up to a region and basically planting a flag and claiming "this is mine now" is rather ridiculous, isn't it? Still, the world we are currently living in has no real undiscovered or unaccounted for land at this point, no matter how spurious prior claims to such land may have been in the past. Given that, I do not recognize *squatter's rights."

As to your last query, I honestly don't know. That's rather farfetched, isn't it?