The Ubuntu packages do not install the library to /usr/local, but rather to /usr/. The library you are showing is from a different source altogether:
jonathan@jonathan-laptop:~$ dlocate libqt-mt.so.3 libqt3-mt: /usr/lib/libqt-mt.so.3.3.8 libqt3-mt: /usr/lib/libqt-mt.so.3 libqt3-mt: /usr/lib/libqt-mt.so.3.3 libqt3-mt: /usr/share/qt3/lib/libqt-mt.so.3.3 libqt3-mt: /usr/share/qt3/lib/libqt-mt.so.3 jonathan@jonathan-laptop:~$
The Ubuntu packages do not install the library to /usr/local, but rather to /usr/. The library you are showing is from a different source altogether:
jonathan@ jonathan- laptop: ~$ dlocate libqt-mt.so.3 libqt-mt. so.3.3. 8 libqt-mt. so.3 libqt-mt. so.3.3 qt3/lib/ libqt-mt. so.3.3 qt3/lib/ libqt-mt. so.3 jonathan- laptop: ~$
libqt3-mt: /usr/lib/
libqt3-mt: /usr/lib/
libqt3-mt: /usr/lib/
libqt3-mt: /usr/share/
libqt3-mt: /usr/share/
jonathan@