Its a replica of the top they wore in the game, any changes to the design would mean that its ceased to be a replica, that would include adding something as simple as an extra star.
The blurb about the top is ‘History Was Made! Be part of it with the Special Edition World Club Challenge Replica Shirt, as worn by the players in one of the most iconic moments in Saints' history.’. Any changes and you could be in to false advertising territory as ridiculous as it seems.
For the O'Neill haters Wigan 4yr deal with Kappa