SIGNED "C.F. MARTIN & SONS", NAZARETH, PA ACOUSTICAL STEEL-STRINGED GUITAR MODEL D-18,1965, serial number: 201723. Mahogany sides and back, all original parts, together with original black, hard cover carrying case; location and serial number stamped inside interior and maker atop fret board and keys in gold paint script - L: 40 1/4 in. Estimate $2,000-3,000