You can read a little about the history of the Horseshoe bar in the Manning Centennial book online.
http://davidkusel.com/centennial/frame-y.htm
Scroll down to Restaurants 202 - 207 on the left side.
Click on that link and then scroll down on the right side to the "Corner Cafe" section.
There you will read a little about the Dubuque company.

This business web page shows some pictures and information on that building.
http://www.davidkusel.com/manning125/street/east9.htm

If you are looking for something more specific about the Horseshoe bar let me know and I can ask a couple of "older" folks around town.