My Understanding, Perhaps Erroneous, Was Callandor Was Made During the Breaking. - Edit 1
Before modification by Joel at 27/11/2009 01:17:04 PM
But Callandor existed, since it was created after the War of Power had caused disruptions in the technical capabilities of the Age of Legends Aes Sedai. So, it seems to me, that Callandor was attuned to Rand because Lews had used it previously during the War, even if it was not his personal weapon.
It and the Stone together. I can't recall since it's been so long, but I believe there was discussion of its completion when Rand went to Rhuidean (perhaps they just discussed its disposition, but I don't know and don't have the books to check right now.)
Despite Be'lal's statements to Rand in TDR, I can't believe swords were used long during the War of the Power. We hear a lot more about shocklances and things like that, and the only time I remember swords discussed as weapons is TDR. Most likely even if Callandor existed before Dragonmount LTT never used it as a weapon, but a Power wrought sword of some kind.