No - VNC uses a script
~/.vnc/xstartup that you can edit as you like.
For instance, mine looks like this, and I run xfce:
Code:
xsetroot -solid grey
vncconfig -iconic &
gkrellm &
xscreensaver -no-splash &
xscreensaver-command -lock &
exec /usr/bin/startxfce4
Eric