Fender Tag "PREP LINE" only. Who has seen one and what does it mean?

[supercommando]

Saw a 1967 fender tag that says PREP LINE and that's it, nothing else. Who has one? Who has seen one on a car? And finally, please, what the heck was it supposed to indicate exactly? Thanks in advance!

 

[fbs63]

I'm guessing it would be the cars used to set up the assembly line during a model year change.

 

[QuickBpBp]

I see them pop up every once in awhile...In Washington too..

https://www.ebay.com/itm/NOS-Mopar-...258447?hash=item288e12570f:g:O5oAAOSw3iFeOsfL

 

[DeltaV]

I see them pop up every once in awhile...In Washington too..

https://www.ebay.com/itm/NOS-Mopar-...258447?hash=item288e12570f:g:O5oAAOSw3iFeOsfL