Correct! As we mentioned recently on Topics, you will be able to redeem your Chocobo Shirt once Adoulin becomes playable:
On March 26, 2013, the FINAL FANTASY XI: Ultimate Collection Seekers Edition will go on sale and those who purchase this special edition will also receive the Chocobo Shirt in-game bonus item. Please note that registration of the Chocobo Shirt campaign code will not be available until Seekers of Adoulin becomes playable.
*The specific time when Seekers of Adoulin content will become playable will be announced at a later date.