apt sources.list disabled on upgrade to 12.04

After a do-release-upgrade, I'm now running ubuntu 12.04 LTS, as indicated below

> lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description:    Ubuntu 12.04 LTS
Release:        12.04
Codename:       precise

However, I find that all the entries in my /etc/apt/sources.list were commented out except for one.

QUESTION: Is it safe for me to edit these, replacing the old 'lucid' with 'precise' in what is shown below?

## unixteam source list
# deb http://debian.yorku.ca/ubuntu/ precise main main/debian-installer restricted restricted/debian-installer # disabled on upgrade to precise
# deb-src http://debian.yorku.ca/ubuntu/ precise main restricted # disabled on upgrade to precise
# deb http://debian.yorku.ca/ubuntu/ lucid-updates main restricted # disabled on upgrade to precise
# deb-src http://debian.yorku.ca/ubuntu/ lucid-updates main restricted # disabled on upgrade to precise

# deb http://debian.yorku.ca/ubuntu/ precise universe # disabled on upgrade to precise
# deb-src http://debian.yorku.ca/ubuntu/ precise universe # disabled on upgrade to precise

# deb http://debian.yorku.ca/ubuntu/ precise multiverse # disabled on upgrade to precise
# deb-src http://debian.yorku.ca/ubuntu/ precise multiverse # disabled on upgrade to precise

# deb http://debian.yorku.ca/ubuntu lucid-security main restricted # disabled on upgrade to precise
# deb-src http://debian.yorku.ca/ubuntu lucid-security main restricted # disabled on upgrade to precise
# deb http://debian.yorku.ca/ubuntu lucid-security universe # disabled on upgrade to precise
# deb-src http://debian.yorku.ca/ubuntu lucid-security universe # disabled on upgrade to precise
# deb http://debian.yorku.ca/ubuntu lucid-security multiverse # disabled on upgrade to precise
# deb-src http://debian.yorku.ca/ubuntu lucid-security multiverse # disabled on upgrade to precise
# R sources
# see http://cran.us.r-project.org/bin/linux/ubuntu/ for details
# deb http://probability.ca/cran/bin/linux/ubuntu lucid/ # disabled on upgrade to precise
deb http://archive.ubuntu.com/ubuntu precise main multiverse universe

Solution 1:

Install Y PPA Manager mate, it's really intuitive: http://www.webupd8.org/2012/10/y-ppa-manager-0092-released-with-new.html

Solution 2:

Check if the Sources actually support precise I checked this source [ http://debian.yorku.ca/ubuntu/dists/ ] and there is a precise folder so renaming the sources to precise should work fine. Although on sources that were marked lucid-security you might want to change them to precise-security.