Okay, then his research is to be considered fact? It's the result of careful research, but it would have to be backed up with broadcast info for every sheet.
Here are a few questions that will help make or break the theory.
How did production schedules run? If a car is 10E, does the build week include the entire week even though it picks up the first few days of November? If a car is 12A, does that week begin on the first day of the calendar month, or the first December day of a production week? And is a production week Sunday - Saturday, or something else? And are these cars from normal 1968 production year, or extended (late '69) production?
Comparing a perpetual calendar to the production info will give a better view.
Kurt gave us the condensed version. He had a head start on this due to his 1st gen Camaro research that weighs very heavily on trim tags. They don't have PHS so the trim tag research was more important. As he states on his site, thousands of tags fit this theory. The chances of coincidence are very small(nil).