Baltwo has a partially correct answer,but I suspect not for the reason he states.
When iWork was updated, Apple did not remove the old iWork '09 versions but elected to place thom in a folder labelled "iWork '09". They were well aware that the new versions would require more development to bring them up to the level of the old apps, where there was missing functionality. Launchpad does not work with folders so, although the apps were in the Applications folder, Apple knew they would not be included in Launchpad.
However, if you take them out of the folder, they should, in theory, appear in Launchpad but they don't. Dragging the apps onto the Launchpad icon in the Dock has no effect at all, the apps are different to the new ones, they have a different nomenclature and their own histories, so they should be in Launchpad. Once there, they can be placed into their own Launchpad folder or not.