False. Unless it's a plist mod or hard system mod, it won't be backed up. You'll need to use a backup tweak like PKGBackup. Alternatively, you can backup your installed packages manually into a list, then after the restore, place the backed up list into /var/mobile/, then restore that list of apps back. Make sure you're signed into your Cydia account before restoring the list or you'll get the HTTP 500 error.
To manually make the list, open up MobileTerminal or an SSH Terminal Client (PuTTy, Terminal, etc) on your computer. Login if you're using a computer.
Run the command dpkg --get-selections > installed-apps.txt
This will generate a text file in /var/mobile/ with a list of installed packages. I don't remember if it backs up the repos as well, but it does for packages. Save this text file onto your computer.
Restore your device, re-jailbreak, place the text file back into /var/mobile. Then run the following commands in order.
dpkg --set-selections < installed-apps.txt
In some occasions there may be a hiccup in the txt file, in which case, you can run
apt-get --fix-missing dselect-upgrade
TL;DR: Simple way to do it is to buy PKGBackup. Free/manual way uses Terminal Commands