While interesting and worthy of further research for sure, I still feel pretty confident that the "extended stripes" we're seeing even in these vintage pics are all examples of either dealer or more likely owner added paintwork. It is odd that so many vintage pics seem to be popping of Z/28s painted like this as of late, but these photos may simply support a theory that it was a popular modification and that a lot of Z/28s were subject to this stripe treatment back in the day. Let's not forget the 6 taillight treatment that was so popular on mid-year Corvettes, immortalized in the words of Jan & Dean's "Dead Man's Curve." Check out
this link for a vintage shot of some brand new '67s on Clippinger Chevrolet's lot complete with dealer added 6 tail light treatment. My point being, by the looks of this pic you'd think the 6 lights could have been a factory deal too, but they weren't, just a popular modification that some dealers would provide if the buyer demanded it. I also think that if the extended Z/28 stripes were any sort of a factory job, even by special request, there would have to be a stencil with a GM part # in some service manual or bulletin somewhere. Dealers would have been responsible for duplicating these stripes if a car was rearended, or needed the tailpan repainted for some reason or another. GM part numbered stencils exist for every other GM stripe application on a 69 Camaro, why not these? I guess until we find an unrestored original owner car with some paper, we'll just have to keep guessing.
