The Body Buck Tag is a small aluminium plate bolted in the engine compartment and painted the same semi gloss black.

Depending upon the model year and the assembly plant, the location of this plate vary:
    - for 1965 and 1966 (dearborn and Metuchen) and 1967 (Metuchen), the plate is bolted in the inner fender, driver side.
    - for 1967 (Dearborn) and 1968-1969 (Metuchen), it's bolted in the inner fender, passenger side near the hood hinge.
    - for 1968 and 1969 (Dearborn), it's bolted on the radiator support, passenger side.

The San Jose assembly plant almost never used that kind of plate, the Mustangs that rolled out San Jose with a body tag are so rare that they are anecdotic.

Body Buck Tags hold codes, including VIN, body color, trim style and color, options and especially the actual build date of the car.

The goal of these plates was to help the workers to know at a glance how to equip the car they work on.

The most interesting plates are thoses of Metuchen cars, because they carry lots of codes.

The first code, 101, state for the number of the car in the body and paint assembly line. this code have no link with the VIN, this code starts at 001 and end to 999, then starts again.
101 mean the car was the 101st in its group.

The second one, 13, state for the assembly line number. Several car with following VIN's generally have the same code here. It starts at 1 and end at 25 (I never seen a code over 25...)
14 mean the car was assembled on the line #13

The third code, 12J, state for the actual build date. This date is generaly around 5 to 10 days superior to the schedule date of the DATA plate, meaning that Ford usually planned to build cars faster than it could be.
12J mean the car was built september 12th, 1968. See the page translater to know your car's built date.

76A, TOP2, 2B state for body and trim style, convertible top model and color.
76A mean convertible standard interior, TOP2 black top with plastic rear window and 2B blue standard interior. See page translater for all other codes.

9T03M101500 is the car's VIN.

P MED BLU M, body color, in code and in real: P = Winter Blue =  medium blue metallic.

X MC PB MO DE PT, the famous option codes. See in the bottom of this page for the meanings of most codes.

BELGIUM, Mustangs made to be exported generally have the destination country punched in their body tag. You can find SPAIN, ITALY, W.GERMANY,SWEDEN, and BELGIUM.

In '64 to '69, Ford USA sent cars by cargo to Anvers, Belgium, where Ford France, Ford Belgium and Ford Luxembourg came and pick the cars they ordered. That's why Mustang sold new in France carry the word Belgium in their DNA.

Beside these codes, the body tag plate has often holes of various shapes: star, heart, square... these holes are quality control marks identifying builders of the car. The "PAINT OK" marks mean the same.
 
 

Here are registered option codes punched in the bottom lines of the body buck tags.
Some of them have a perfectly easy to understand meaning: GT for GT package, 4S for 4 speed tranny, but some others are not so sure if not completely unknown.

AC or AIR COND: Air Conditioning
BL: Backlite louvers on '69 fastbacks
CL: Convenience Lights
CG: Convenience Group
C/O: Customer Ordered
CS: Competition Suspension
CT: Collapsible spare Tire ?
D: Dealer ordered
DB: Disc Brakes
DE: Dual Exhausts
ET: Exterior Trim package 1967
EX: export model
FD or FDS or FDRS: Fold Down Rear Seat (on Fastbacks)
GT: GT option, this code was used in 1968 and 1969, 65 to 67 use "PIO" code
HP: Handling Package
IDG: Interior Decor Group
IT: Integral Turn signal, on '67 and '68 hoods
K: 289 high performance engine ?
LP: ???
LT: ???
MC: Middle Console
MO: Rocker Panel Moldings, on 1969 models
MP: ???
MT: Manual Top (convertible)
PB: Power Brakes
PS: Power Steering
PT: Power Top (convertible)
PV: Power Ventilation
PI0 ou PI: Performance Image Option: the GT option, in 1965, 1966 and 1967
-R:  radio delete
RM: Remote Mirror
SA: ???
ST: Stereonic Tape system
TC: Tilt away steering Column
TT: Two Tone paint ?
VINYL ou VR: Vinyl Roof
V8: V8 engine
3S: 3 Speed transmission
4S ou 4SPEED: 4 Speed transmission
X: export model