Serial number 12915 was stamped during October/November 1917 and was shipped to William Lewis & Son in Chicago on December 26, 1917.

Although the tuners are reported as newer, they do appear to be period-correct Dinsmore & Jager #26 machines.

The ebony pyramid bridge is a replacement.

Style 28 features:

Back and sides: Brazilian rosewood

Top: Red spruce (Adirondack)

Purfling: Herringbone

Binding: White celluloid

Backstripe: Zig-zag pattern

Other period features:

Scalloped X-bracing

Ebony fingerboard

Slotted square and diamond Japan pearl inlays

Ebony pyramid bridge (replacement)

Ebony neck reinforcement

1-7/8" neck width at nut

C. F. Martin stamp on back of headstock

No style stamp

Photos courtesy of Elderly Instruments.

At the time of writing (September 6, 2019) this guitar is available at Elderly Instruments.