Those instructions are for manual installation, so you can ignore them since you're installing from a package instead.
Installing the package should be the only thing you need to do. However, there's currently an unrelated bug that's preventing nautilus-emblems from being loaded.
Solution
The bug has been fixed in what will become Ubuntu 13.10. If you wait until October and then upgrade Ubuntu, nautilus-emblems should work.
There's been no indication yet of plans to release a fix for Ubuntu 13.04.
Temporary workaround
If you're feeling adventurous, you can try building the unreleased package for Ubuntu 13.04:
- Install
build-essential, debian-keyring, and the build dependencies for python-nautilus.
Save the three source package downloads to a temporary location and run:
dpkg-source -x nautilus-python_1.1-3ubuntu3.dsc
cd nautilus-python-1.1
dpkg-buildpackage -b
Install python-nautilus_1.1-3ubuntu3_amd64.deb.