That's the only sign I've ever seen as well, going back to when I first clinched it a few years back. Nebraska has no official business loops, it just depends on how well cities want to sign them. Nebraska City does a good job, Fremont... doesn't. Business 30 signage is spotty as well, and may not ever be signed on the west end again with the reroute.
Both the US 30 and US 77 reroutes got approved by AASHTO as well.