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.
So that sign is for the Nebraska-specific Lincoln Highway "scenic" byway, not for the national route as far as I can tell.
I wasn't paying that much attention as I drove by. I imagine most drivers (myself included) would not notice a difference between the "national route" signs and the "Nebraska-specific" signs. In this case I'm not sure it matters as the section was concurrent with US30, but it could lead to further discussion as to what type of signage is needed for inclusion in the usatr system. I wonder if I've opened a can of worms here.