Well in general yes. But if you really want a
minimal installation it's a little bit more work than that.
Here you can see which packages gnome-core pulls (e.g. evince, brasero, etc.). If you think these are too much you could install gnome-session instead of gnome-core. When you use the --no-install-recommends option you'll see a list of recommended packages when you're asked to confirm the action. From that list you can get an idea about other packages that might be good to install.
But before you do that I would install a minimal xserver. To do that you install the packages xserver-xorg-input-evdev and xserver-xorg-video-<drivername>. So you choose which video drivers you want and only install these. If you install gnome-session before that it will most likely pull all video drivers and other things. That's because once you installed ONE video driver the xorg video driver dependency is satisfied but if none is installed it will simply pull xserver-xorg-video-all if another package asks for that dependency.
I think unless you disable the automatic installation of recommended packages in apt.conf, 'apt-get upgrade' might still pull recommended packages.
When you're done with the package installation you should save a list of installed packages to a file with 'dpkg --get-selections > installed_packages.txt'. Then if you want to go back to that state you just do:
dpkg --clear-selections
dpkg --set-selections
< installed_packages.txt
apt-get dselect-upgrade
That will remove all non-essential packages not mentioned in installed_packages.txt.