Unlike Moonlet, Dalamud Horn* and White Ravens were specifically and in no uncertain language declared to be exclusive to 1.0. Moonlet was not mentioned as part of those announcements so it's "fair game" to be reintroduced in ARR.

*The post "Discontinued Content in FINAL FANTASY XIV: A Realm Reborn (07/27/2012)" is no longer available on the internet from official sources. However, it can still be accessed through my 1.0 Lodestone archive in the "Lodestone Announcements and Game Updates" folder.