Serial number 90987 was stamped on March 28, 1945 and cleared final inspection on June 25 that year.
This guitar is one of the earlier war-time Martin guitars that got the re-issued steel T-bar neck reinforcement.
Martin, due to war-time restrictions, had been forced to eliminate the steel T-bar neck reinforcement in early 1942 and replace it with an ebony bar neck reinforcement. Hoever, Martin received a supply of steel T-bars in January 1945 that last to the end of that year. Supply of the steel T-bars was spotty in 1946 and again caused some guitars to be made with the ebony neck reinforcement. Regular supply of the steel T-bar didn't become available until early 1947.
The tuners are late war Kluson 502N machines with white celluloid buttons (this is still a tentative identification). It should also be noted the bushings are missing on the front of the headstock.
Style 28 features:
Back and sides: Brazilian rosewood
Top: Sitka spruce (probably)
Binding: White celluloid
Backstripe: Zig-zag pattern
Other period features:
Ebony belly bridge
Photos courtesy of Steve Swan Guitars