I was just in Nebraska this weekend and saw
this sign along US30 near Sutherland, NE.
While I can't attest to how well the route is signed through the state, there are certainly sections that are concurrent with US30 that are not yet in the HB.
I was curious about the route and found this
Lincoln Highway Map which could be useful. It seems to show all the various routings over the years. Maybe it will be helpful to anyone researching this route.