Serial number 199572 was stamped on December 23, 1964 and cleared final inspection on February 11, 1965.
The D-21 guitars were made of Brazilian rosewood like the D-28 guitars but were characterized by plainer appointments and black binding, although the zipper backstripe was retained.
The tuners are Kluson K-324 machines.
Back and sides: Brazilian rosewood
Top: Spruce (probably Sitka spruce)
Photos courtesy of Steve Swan Guitars.