I looked for drive shaft stripe definition for over two years before I found a similarly equipped vehicle as mine, same assembly plant, and reasonably close build date.
I hope you find it much sooner than me, but you need to be patient.
Keep in mind that most people want a bright red convertible that looks good on the outside and sounds mean. A smaller subset want the bottom to be clean, and by clean that could be a shiny painted black, or new aluminum driveshaft. There is a small subset of people that are looking for factory original details.
When you add 50+ years of dirt and grime, the size of the set shrinks and continues to do so.
Lastly, it should make sense, based on value, that the Boss, CJ, Shelby, HiPo, GT, Mach etc. variety cars, will result in significantly more research and better documentation than a 6 cylinder car.
In some respects, those that restore the 6 cylinder cars are in a tougher position.
Patience is required. This is why Jeff noted that in this case the stripes are easily added at a later date.