Sure seems likely... nice research work!
Think this is "Joe"?
http://www.ancestry.ca/genealogy/records/joseph-trutnovsky_2...
Born Scotland SD, died in IL.
Interesting pencil markings... I would normally dismiss such findings, but as Gene notes if you need a snooper to get to them, and also most graffiti isn't so "formal" looking with a guys name and the city he is from (which isn't a nearby city, but from South Dakota) so I suppose it could be from original construction. Interesting.
This would have been for the FIRST use of the designation "Illinois Highway 18." In 1927, the IL 18/SBI 18 designation was removed from this highway in favor of US 34. The "IL 18" designation was re-used by IDOT on the current IL 18 route starting in 1939, re-designating IL 89B and IL 89C.
The Water Street Bridge may or may not have carried US 34 for a few years. There is one former through-town routing of US 34 via Union St. in Earlville, in addition to the current routing. The bow to the south on Union St. where it crosses Indian Creek suggests that the current bridge at that location might not be the "original" Union St. Bridge.
The name in the last photo is Frank Johnson, Philip, South Dakota. I was able to find this, might be him: http://www.mocavo.com/Frank-C-Johnson-B1904-Philip-Haakon-So...