Nah, it's confirmed in the XII ultimania that Tactics takes place a thousand or so years after FFXII, the events surrounding St. Ajora take place a short time after XII.

Balthier tells Ramza he found the Cache of Glabados once and "ended up here", meaning FFT's Ivalice 1000 years in the future. I'm guessing after the events of the game he finds it again, returns to his time, and then tells Vaan to come meet him, 2 years after the end of the Great War in FFXII.