How to Read Gibson Serial Numbers
Dating a Gibson guitar by serial number is more complex than it might appear — Gibson used several different serial number systems across their history, and many of these systems used overlapping ranges that make exact year determination difficult. However, combined with Factory Order Numbers (FON) and pot codes, serial numbers can usually narrow the production year to one or two years. This guide covers every Gibson serial number system from 1935 to the present.
The Batch Letter System (1952–1961)
From 1952 through 1961, Gibson used an ink-stamped serial number with a letter prefix followed by four to six digits. The letter indicates the production batch, not a specific year — and because Gibson produced multiple batches per year, the same letter may appear across two consecutive years.
Key batch ranges for collectible eras:
A 3000–A 4999: 1952 (first Les Paul Standards) A 27000–A 29999: 1958 (Burst begins) A 30000–A 34999: 1959 (peak Burst era) A 35000–A 39999: 1960 (last Burst year) A 40000–A 44999: 1961 (Les Paul becomes SG)
Because these ranges overlap between years and were not applied strictly sequentially, the serial number alone can usually place a guitar within a two-year window. For single-year precision, pot codes are required.
Factory Order Numbers (FON) (1935–1961)
The Factory Order Number (FON) is separate from the serial number and appears as an ink stamp inside the body — visible through the f-holes on electric guitars or the soundhole on acoustics. FON stamps are generally more precise for dating than serial numbers, because they were applied when the guitar entered the production queue rather than when it was completed.
FON format examples: '8 1234 5' (year=1948, batch=1234, position=5). The first digit or digits indicate the year; the middle portion is the batch number; the last character indicates the guitar's position in that batch.
From 1935–1941: A letter followed by numbers (A, B, C... + batch number) From 1942–1947: A number prefix indicating the year (2 = 1942, 3 = 1943, etc.) From 1947–1961: The last digit of the year is the prefix
How to Read Pot Codes
Potentiometers (volume and tone pots) are the most reliable dating tool for pre-1977 Gibsons. The pot is date-coded by its manufacturer and installed shortly after manufacture, typically within 6 months.
The pot code is a 6 or 7-digit number stamped on the back of the pot body. Reading a typical code like 1374703:
137 = manufacturer code (CTS in this case) 47 = week of year (47th week) 03 = year (1903? No — 2003? No — context determines century. For vintage guitars, assume 1900s: 1953, 1959, etc.)
For vintage instruments, the format is: [manufacturer][week][year]. Gibson used pots from CTS (137), Stackpole (304), Centralab (134), and others.
- ›Remove the pickguard or control plate to access the pots
- ›Look for the stamped number on the back of the pot housing
- ›Common format: 3-digit maker code + 2-digit week + 2-digit year (e.g., 1372856 = CTS, week 28, 1956)
- ›The latest pot date in the guitar is the earliest possible production date
- ›Pots were typically installed within 6 months of their manufacture date
The 8-Digit System (1977–Present)
In 1977, Gibson introduced an 8-digit serial number system that encodes the production date directly into the serial number. This system is still used today:
Format: [Y][DDD][YY][P][PPP] Example: 90071521
9 = first digit of production year sequence 007 = day of year (the 7th day = January 7) 1 = year (last digit; in context: 1991) 521 = production sequence number
More specifically: Digits 1, 5, 6 form the production number; digits 2–4 are the day of year (001–365); digit 8 is the last digit of the year. For the example 90071521: day 007, year ending in 1 = 1971, 1981, or 1991. Combined with the first digit and production sequence, the year can usually be determined unambiguously.
Frequently Asked Questions
How do I find the serial number on my Gibson guitar?
On most Gibsons, the serial number is ink-stamped on the back of the headstock. On some older models and acoustics, it may be on a paper label inside the body visible through the soundhole or f-holes. Very old Gibsons may have the number on an interior brace.
Why does my Gibson serial number match two different years?
Pre-1977 Gibson used a batch-letter serial system where numbers were assigned in production batches, not sequentially by year. It's entirely normal for a serial number to fall within the range of two consecutive years. To narrow it to a single year, check the pot codes inside the guitar.
What is the most reliable way to date a vintage Gibson?
The combination of pot codes (the date stamps on the backs of the volume and tone potentiometers) and the Factory Order Number (FON, stamped inside the body) provides the most reliable dating. The serial number narrows the range; pot codes narrow it further; and the FON, when present, can often give the specific production batch.
Can I date a Gibson by the pickups?
Pickup style can help bracket a production date. PAF (Patent Applied For) pickups are from 1957–1962; 'Patent No.' pickups from 1962–1965; T-top humbuckers from the late 1960s onward. However, pickups are easily swapped, so a guitar with original pickups can be dated by them, but a guitar with replaced pickups cannot.