UB-1 banjo-uke that I have at home (above) has a logo on the headstock that is hand-lettered in what looks to be metallic gold enamel paint. This uke is probably from around 1926. Some earlier, higher grade models of the Gibson banjo uke have lettering made of pearl inlay (placed on a slant). Later models of this same uke have what appears to be "The Gibson" in a stenciled typeface which looks different than this typeface.
The L-1 Gibson guitars from this period have hand-lettered silver logos.
The thickness of the lettering varies on these instruments and there is no mistaking that a small brush and a steady hand did this work. I can just picture the artist sitting in the factory doing this particular job as I have done it myself on my own fine art ukes (link, Tickler link)
In the late 20s, Gibson also offered a few fully hand-painted models such as the Pointsettia Uke (recently on ebay) and a guitar with an Italian street scene painted on it.
I love the fonts and hand-lettering of the 1920s. And I love the early vintage instruments of Gibson.