No it will not back up your old rom. You would have to get that first.
In a post dated the middle of last month over at xda they said US Cellular is one of the only ones left that they dont have an original official rom to reflash if you need to. They said it is being worked on. Im not sure how long til its released but it might already be soon.
Dcd has already posted a rom dump of the official USCC rom. But Im not seeing anything other than that.\\
EDIT: If your feeling brave heres the link to the rom dump...its in post #6 by dcd1182
http://forum.xda-developers.com/show...t=Cellular+rom
and here are some directions that will tell you how you might go about making that a flashable rom. I looked at it and quickly became overwhelmed. lol. I couldnt figure out where in those directions to start at. Its directions for a hermes rom but mogul will be similar.
http://wiki.modaco.com/index.php/How...t_a_Hermes_ROM