I don't know if there will be any revisions or additions to the Lorebook before the content patch in June, but right now I have repeatedly found quests when searching for ones that I missed which are not implemented yet.
For instance, there are a series of quests for level 27 which take place in the town of Oatbarton norht of the Shire (although the lorebook places them in "The Shire"). This town currently doesn't exist, but is discussed in the preview for Shores of Evendim! This has created a headache for myself and others as we try to scan other sources to match up quest titles only to find nothing.
If the lorebook will be rolled out of its beta version before June, please help us to distinguish between the quests currently in game and those reserved for future content.