It has been years since I have owned the cars and I didn't keep the documentation.


It should not be too surprising with your knowledge of GM and how they rarely begin or end a process at a year change. There are many changes that take place late in the year.

I imagine the subject was debated with gusto because there will be people that think they have seen everything and others who know what they have seen.

There are cars with missing engine vins through the years. I have had the privledge of working on the number stamping machines on assembly lines and if they don't work the line keeps moving. It would be nice to have "cut and dried" rules but the factory is an unpredictable place.
Jim