According to SE Chocobo Whistles are being removed from the game for the conversion.

So now I ask who does not have their Whistle all of Hyperion should help those that cannot get their Chocobo Whistle before Nov 1.

here is the proof----------------------------------------------------------------

Items Removed from Game
The following items will be removed from player inventories.

Guild Marks
Guild Treatises
Key Items

Players are advised to exchange all guild marks and treatises before November 1st, 2012. Upon release of FFXIV: ARR, it will also no longer be possible to receive guild mark refunds for previously purchased abilities.

Special abilities and access to content obtained through key items will not be revoked. Player progress will be tracked through alternative systems.

Example: Chocobo whistles will be removed from game, but players in possession of one will retain the ability to summon their chocobo.

At this time, we cannot comment on how changes to game systems will affect each and every item. However, rest assured that we are dedicated to preserving fairness and equality between players who have obtained these key items and players who have not.

Example: In FFXIV: ARR, all players will have unrestricted access to the city-state aethernets, which will render aetherpasses obsolete. Players already in possession of these passes will receive 40,000 gil in compensation (as per the redenomination, 1/10 of the original purchase price). Players who purchased the aetherpasses with company seals will be recompensed in gil.

Players in possession of the goobbue horn, which is no longer obtainable as of patch 1.23a, will retain the ability to summon the goobbue mount. The mount will remain unobtainable in FFXIV: ARR.