Did some driving around Guam in December and clinched the highway system. There were several routes in the HB that were unsigned, at least as of December 2019, though I drove them anyway.
Guam is unusual in that there aren't really reassurance shields, but intersections of the routes are signed. I thoroughly checked intersections at the start/end of the highway, as applicable.
GU3A was unsigned.
GU8 was also unsigned.
GU24A was unsigned, though a mention was made of it on a variable construction sign.
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