It always adds to the story of a particular instrument when the purchase documents are available. Here is another great example.
Serial number 73316 was stamped on September 22, 1939 and cleared final inspection on December 4 that year.
As can be seen from the documents below this guitar was sold by Wilson Music Co. who was a Martin dealers in Oshkosh WI. This guitar was ordered by Wilson Music on November 22, 1939 and was certainly shipped on December 4 or very shortly thereafter. This guitar was in stock at Wilson Music for the better part of a year before it sold on October 26, 1940.
The tuners are Grover G-98 pointed plate machines.
Style 18 features:
Back and sides: Mahogany
Top: Red spruce (Adirondack)
Binding: Tortoiseshell celluloid
Back stripe: None
Other period features:
Ebony belly bridge
Steel T-bar neck reinforcement
1-11/16" neck width at nut
Tortoiseshell celluloid pick guard
Dot fingerboard inlays
Decal on front of headstock
No C. F. Martin stamp on back of headstock