The question is whether that man was the original, or a copy, or neither AT THE TIME THE INCIDENT OCCURRED, which we only learn about AFTER Farpoint.
That's the reason I posted:
unless someone can come up with some hard evidence that there was some in-universe confusion (among his companions) or confirmation going forward.
There was never a question about Will being the original after that episode, unless there's some proven, on-screen dialogue or scene that confirms or even entertains the idea of it. Of all of the TNG staff interviews I've read, I cannot recall one that said Will was--undeniably--the copy, not the original man.