You are right 300Six, Vikings were the first documented Europeans arriving to America.
About the documentary... Documentary makers are not to be supposed to know all of everything, but they must learn about what they are talking in order to not to make fiction. If they produce fiction they can't sell it as a documentary.
Nevertheless I'm not blaming the people who produced this "documentary", I'm blaming the scientifics who studied the artifact. Some of their premises are true, like the most probable origin of that piece of iron. But their affirmation about rewritting history and the mark of the axe are clearly incorrect and they know it.
I'm sorry but the history of the mark is short, there isn't any appreciable mark there. If the mark they discovered was true be sure they would explain all about it, but they are very evasive in this concern. I have talked the experts consulted here, they say they there is no mark in that piece of iron, these experts contacted to other experts from the other side of the ocean and those also say they don't see any mark there. Both experts have been consulted by those who studied the artifact and experts from both side of the ocean have said the same to them...