Serial number 75042 was stamped on May 10, 1940 and cleared final inspection on September 6 that year.
The tuners are Grover G-111 machines with un-seamed butterbean buttons.
The guitar comes with what appears to be a style C case.
Style 28 features:
Back and sides: Brazilian rosewood
Top: Adirondack spruce
Back stripe: Zig-zag pattern
Other period features:
Scalloped X-bracing, rear X-braces
Ebony belly bridge
Steel T-bar neck reinforcement
1-11/16" neck width at nut
Tortoiseshell celluloid pick guard
Slotted square and diamond fingerboard inlays
Decal on front of headstock
No C. F. Martin stamp on back of headstock