Serial number 26709 was stamped on October 2, 1926.
The brass tuners are probably Waverly G-2 machines with white celluloid buttons.
The ebony straight bridge is a replacement.
Style 18 features:
Back and sides: Mahogany
Top: Red spruce (Adirondack)
Backstripe: Single line of rosewood purfling
Other period features:
12 fret neck
Ebony straight bridge
Nickel silver bar frets
Graduated fingerboard dot inlays
No style stamp
"C. F. Martin & Co." stamp on back of headstock
At the time of writing this guita isa availabe at Schoenberg Guitars (http://www.om28.com/ProductDetail?product=P180627002)
Photos courtesy of Schoenberg Guitars