These guitars are thoroughly inspected and prepared by Martin craftsmen at our factory and carry a limited lifetime warranty. White binding on body (w/b/w/b/w.) Rosewood overlay on 1st generation "Spatula" headstock (Sigma w/Σ logo.) Headstock and fretboard are single-bound in white. Laminated rosewood sides and 3-piece back, ala' D35.
All other text was printed in black ink, or stamped on in ink by the manufacturer (model and serial numbers.) 5-digit, or 8-digit serial numbers. Being a mid-year change, some continued on with the "Purple" label, though with the new serial number designation preceded by an "S" or an "E" This is prefixed by the serial number assigned to the instrument and followed by an ink stamp of the model number. L-R as seen through the sound hole: Serial number, "Brand," Model number.) The serial numbers on these instruments were often preceded by the letters S or E; e.g. It is currently believed that this transition was complete by 1979. Some solid body electric guitars were made by Tokai Guitars Company, LTD. After Sigma musical instruments were built in Japan, Korea, Taiwan and finally Indonesia, they were sent to Martin & Co. The early 70s models (1970 -1975) can be distinguished by a more squared peghead, shaped similarly to that of a "spatula." The logo consisting of a gold decal with the single word in block lettering SIGMA surmounted with the Σ symbol (the Greek letter sigma), in mother of pearl. There were only two models, labeled "Sigma Martin USA DR-28N and DR-35N," "N" for Nazareth. The original factory brochure also states components were processed and finished on the same production line as regular Martins. In 1978, model designations were added to capitalize on Martin model numbers: the DM-18, DM-19, DR-28, DR-28H, DR-35, DR-41, and DR-45. Pegheads & Logos Sigma guitars made in Japan from 1970 through 1983. The affixed warranty card was amended to read..."Your D-10 '9' (or D-10 '8') is not warranted against cosmetic defects." In the years of 1981 & 1982, Martin imported partially assembled Sigma guitars from Japan and the assembly was completed in Nazareth, Pennsylvania.