Mark is correct numbers assigned for the second of two rotation number each received (one for body and paint - one for the second half of the assemble, one we find on the cars typically) was 001 - 999 at San Jose.
At that plant they ran 4-5 different lines each with numbering and as you mentioned since Cougars were built on the same line in 68 the numbers on that line included both types of cars. The numbering system had nothing to do with shift, day or anything - just a way of numbering individual cars in a group so the line workers could identify, organize and keep stiff going . I believe that 1 was the first car on the first day and every 1000 after that
till the end of production according to the workers and managers I've spoken with
Where did you find your car's rotation number? There are at least a dozen locations (approx) I can think of
Mark - lucky you on meeting one of the workers. Yes its a surprise when it happens. Now to mine the info and start comparing what they say.