The handmade title on the cover for the 1939 edition of “A Wand’ring Minstrel” [from Gilbert and Sullivan’s “The Mikado”] was rendered with a round nib lettering pen in an Art Deco style.
This type design is now available as Cover Letter JNL in both regular and oblique versions.
However, the font’s name is a bit of a pun, as it has nothing to do with cover letters, but rather the lettering found on the cover of the sheet music.