Gibson Factory Order Numbers
Do you own a Gibson acoustic from the 1940s or '50s? Chances are, your guitar carries a factory order number (FON) instead of the typical serial number.
If you’d like to learn more about your vintage Gibson acoustic, feel free to get in touch — we’re happy to help.
What Are Factory Order Numbers?
Shortly after Gibson was founded in 1902, the company began using factory order numbers to track and identify their instruments. For most acoustic guitars from that era, FONs are ink-stamped on the neck block inside the body, usually consisting of a letter followed by a batch number. This system was in place until around 1960.
Gibson's Golden Age: 1932–1942
Between 1932 and 1942, Gibson used a clear alphabetical system to organize their FONs:
| Year | Factory Order Letter |
|---|---|
| 1935 | A |
| 1936 | B |
| 1937 | C |
| 1938 | D |
| 1939 | E |
| 1940 | F |
| 1941 | G |
| 1942 | H |
World War II Disruptions
Material shortages and labor challenges during World War II caused inconsistencies in FONs. Some guitars lack FONs entirely, while others have numbers stamped in unusual locations, such as the back of the headstock instead of the neck block.
Here’s a rough breakdown of FON batch numbers during and after the war:
| Year | FON Batch Numbers |
|---|---|
| 1943 | 9xx – 22xx |
| 1944 | 22xx – 29xx |
| 1945 | 1xx – 10xx |
| 1946 | Limited data |
| 1947 | 700 – 1000 |
| 1948 | 1100 – 3700 |
| 1949 | 2000s |
| 1950 | 3000 – 5000 |
| 1951 | 6000 – 9000 |
Postwar FON System: 1952–1960
By 1952, Gibson had resumed a formal FON system, reversing the alphabetical order:
| Year | Factory Order Letter |
|---|---|
| 1952 | Z |
| 1953 | Y |
| 1954 | X |
| 1955 | W |
| 1956 | V |
| 1957 | U |
| 1958 | T |
| 1959 | S |
| 1960 | R |
While a few rare 1961 Gibsons have been found with a Q FON, the company soon shifted to traditional serial numbers — a system they continue to use today.
If you’d like help dating your Gibson or learning more about its history, don’t hesitate to get in touch with us!