I picked Archaic because of the Timeline of the Theban Cycle and the prominence of Delphi in the stories, I put 'probably' on it because of the references to Pelops, grandfather of Agamemnon and Menelaus from the Trojan War, and Lauis, Oedipus's father. The Theban cycle was written down sometime around the 750 and 500 BC, and with so much revolving around delphi I've always assumed Pelops was shoe-horned in to add to the atmosphere of woe. Whichever, not classical era.

From the original era question, when naming characters from Ancient Greece:

Archaic Greece 800-480 BC
Classical Greece 510 BC to 323 BC (Death of Alexander)
...
Socrates, Plato, Aristotle, Alexander the Great and any of their various contemporaries would be classic era, Oedipus Rex would probably be Archaic.

If you had this character and disagreed, you could easily have raised the matter at the time, nobody would have thought it weird to have challenged that or automatically assumed you were he, so why didn't you? I think it is very unrealistic to assume you missed that, the post was obviously pretty prominent, it named you by character, you'd not be having problems now if you said Archaic or Late Helladic. Nor of course does Yuna's choice matter since you didn't know who she was when you gave an era, but she places it as Archaic to classic, which implied she took the date off the Theban Cycle, note the overlap for the Theban Cycle, as late as 500 BC, and the overlap listed for Archaic and Classical Eras, and again my 'probably' comment. The stories are likely even older than that.

Here's the problem, it seems very unrealistic that you could see your characters name linked to an age that explicitly and not take note of it, so it would seem to me that it wold be natural for you to mention that in your claim, what's more, it should seem that would have strongly encouraged you to check the date throughly, decreasing the odds of making the mistake and I would think strongly increasing the odds you would bring it up when you claimed, if for no better reason than to dispute it and let everyone know that the apparent era mistake is a conflict you were aware of, not a mistake that might imply guilt. You jsut don't seem to have had your character on your mind to a degree which would seem realistic to me.