Ok, if it's a question "gut feeling", there's no discussion. You have yours, I have mine.
Just didn't want to leave without addressing a couple of points...
This sword looks to me as having been cleaned/tweaked/restored/"improved" some time ago. Also, this specific item has a typology that doesn't make cleaning it a really difficult task. As such, its condition doesn't seem to me to be particularly noteworthy. It is well conserved, yes, but, not astonishingly so, at least to my eye.
About having seen "almost completely (for its 'age') rust free 17th century swords"... yes. Dozens. Not accounting for the ones in museums. The vast majority of them having spent a good deal of their life in rather dry environments, and at some point "cleaned" in order to put them on the market, and more or less taken care of since then.
But I'm afraid that at the end it's a question of your experience ("gut feeling") and mine. And this is a game I don't want to go into, here
Do I think it's original? Well... quite. At least a good deal of it. To the point of putting money on it? Well, on the right circumstances... yes. But, again, this just means that you and I do disagree. And that's what makes life interesting, I guess
Best regards,
Marc