I guess they did. Most of the time the bonuses include appearances, league position, CL success etc., and they usually give guarantees to the selling team that the bonus money will soon be paid. Udinese wouldn't have sold the player if these 11.5m eur were paid only if Barca wins the CL.
In any case, if some of the bonus clauses are yet to be activated, then Barcelona will be even more willing to sell.