The guitar in this entry is a 1941 D-28 "herringbone".

It has rear-X bracing and the neck is 1-11/16" wide at the nut. Typical of other D-28 guitars of the period is has the scalloped braces,"zig-zag" back stripe and the distinctive herringbone purfling.

The tuners are period correct Kluson 511 machines. These early Klusons have a coined rim around the base plate and full thickness gear cogs.

At the time of writing (March 6, 2019) this guitar is available at Folkway Music.

http://www.folkwaymusic.com/vintage-instruments/martin-guitars/1941-martin-d28-1018/

Photos courtesy of Folkway Music.