http://www.mmcdetroit.com/Certicards/
This is a break down of my certicard..
the vehicle CERTICARD was placed inside the glove compartment and in 1966 -68 it was moved to a special black plastic holder (Part # 2579740) that was in engine compartment.
The CERTICARD identified the vehicle VIN number, select option codes and the original owners name and address for warranty purposes.
On the Certicard, the top line is the VIN:
RS23 = Plymouth GTX L= 440 engine 7= Model year 1967 1=Assembly plant = Lynch Road, Detroit, MI 159220= Sequence number
Line two of Certicard: P6X= interior code= Sport;vinyl bucket seats; black GG1= exterior color = Forrest Green T3= transmission code= Manual SG= this would be SA meaning standard axle meaning no Sure Grip I20I= Scheduled production date. The "I" was used for a "1" so this means 10 (October) 29th.
P6F=interior code Sport;vinyl bucket seats TT1 = medium copper metalic T5= tranny = automatic SA meaning standard axle meaning no Sure Grip I006 Production date