Gibson Serial Number Check -
A nine-digit number beginning with “14” (year), then a space, then a letter indicating plant (e.g., “C” for Chicago), followed by six digits.
YDDDYRRR
Look through the bass-side f-hole to read the paper label. Some historic models also stamp a secondary Factory Order Number (FON) on the inside wood surface. Modern Era Identification (1977 to Present) gibson serial number check