There are no dumb questions, only sometimes irrelevant answers
I didn't check for other apps but at least kdegames run with only kdelibs installed.
This stand for the time being, as I am not sure that in the future (beginning with KDE 4.7) all KDE libraries will be included in the kdelibs packages. Let's quote Alien Bob's blog
The old “monolithic” source tarballs are now being split into many additional tarballs for individual applications. This means we have rewrite our scripts and possibly add a lot of packages.