There's a chance that you misspelled Tirano as well Freece.
Tirano is the small city on the border of Switzerland and Italy at the end of the Bernina Express, and the train goes down the east side of Lake Como and on to Milano. Indeed on this train only a nice Regionale ticket (validated) needed, as mentioned above.
On the other hand, could you have misspelled that and mean Torino, the big city where FIAT cars are made and is where the fastest TGVs from Paris come through on the way to Milano and onwards to the east and south. Having a Freccia there makes a lot of sense, and yes, you should be able to get onto one with a reservation bought one day ahead. If, rarely, the train you want is full so you can't get a short notice reservation, the next train likely will have room. The further out the better, of course.
This all presumes of course that you aren't trying to travel at a particularly busy time, like the day before a holiday - in which case all bets are off.....