Gibson factory order numbers

What a factory order number is

A factory order number, usually abbreviated to FON, identified a batch of instruments moving through the Gibson factory together. It was an internal production control number, not a customer-facing identifier, and it was applied at the start of a batch rather than at the end.

That distinction matters. A serial number identifies an instrument. A FON identifies the batch it was built in, which is why two guitars can share a FON and why the number often appears with a rank letter or digit indicating position within the batch.

Where to find it

• Stamped inside the body of hollow and semi-hollow instruments, visible through the f-hole with a torch and a mirror.
• Ink-stamped in the neck pocket of solid-body instruments, which means removing the neck.
• On the back of the headstock on some older instruments, alongside or instead of a serial.

Why we do not decode them

FON dating depends on published year-code tables that vary by period, by plant and by instrument type, and the numbers themselves were reused. Getting it right requires knowing what the instrument is before you start, which is the opposite of what a serial lookup does.

Building a decoder that accepted any FON and returned a year would produce confident answers that were frequently wrong. That is precisely the failure mode this reference exists to avoid, so we would rather tell you what you are holding and point you at a specialist.

Telling a FON from a serial

Common questions

My Gibson has two different numbers. Which is the serial?

The serial is normally on the back of the headstock or on the label. A number stamped inside the body or in the neck pocket is more likely to be a factory order number, which identifies a production batch rather than the individual instrument.