Thinking it might be true about Dale's Jamacan grandmother
Would be some twist if it turns out Dale really was Joseph's father. I know even Nancy believes John Redcorn was the father. Though Dale believes Joseph is his son. Maybe he had a grandparent that Nancy could have thought she was lying about being the reason for Joseph's colour.
Watched the season 3 episode about hunting deer recently. Joseph talks like Dale did with his theories and when John Redcorn offered him his ancestral knife he didn't really care. Maybe Dale really is Joseh's father.