So the next time I went that way on (8-16-13) I took a closer look at the street signs. Sure enough. The signs out on IL20 say Farewell Bridge Road, but the street signs at the crossings say Farwell Bridge. I am pretty sure it is actually Farwell Bridge.
I passed this on to the Stephenson County Highway Department. I don't know if the signs that are wrong belong to them or to the state. But, they can probably let whoever it is know.
I was back in Freeport the other day and noticed the signs had not been changed. No response from the county so I sent an email to the state DOT yesterday. I got an email back today saying they are going to "investigate your concerns". That's an improvement over being ignored.
The signs on route 20 have been changed. See this post.