OK Mike, I should have said they "subtracted" 100000. 100083-100000=83. Another "typo", right. Like the typo in our Tip Section for 1956-1959 that says 001001. The sequence started at 10001 in 58. It happens to all of us and in your posted "Official Documents".
If it helps the post, I agree with starting at 0 units, instead of my idea of x...xx2 is the first unit. I didn't want to be a Chatmaster anyway. I do thing the bank analogy was quite good, Aye?

One of the documents you posted is dated 1958 but uses a 1952 example. I did not know which official specification to use since the 1952 and the 1958 vehicle identification section is different, as you will see below. Another goofy part of the document you posted. Some of my comments were trying to factor 1952 and 1958.

Chevy kept changing the number of zeros and the inclusion of all series, or each series, to be in the sequence. As per below. They started selling so many they must have run out of numbers.

There are typos, misinformation on Documents, opinions, meanings,Tips and theories on this most interesting post.

Here are some actual facts from the only known "Official Documents", The GM Heritage Center Collection of Chevrolet Corporate Office year specific Specifications. I'm glad to see any other official Specification. Not a catalog, salesman's memo or any of the one million blogs repeating each other.

1. 1952 unit number" "Each series separately numbered in sequence starting with 1001 at each plant."

2. 1958 unit number: "Begin with 10001 at each plant regardless of series"

3. 1964 sequence: 100001 "Starting unit number at each assembly plate regardless of series."

4. 1965 unit number: not found

5. 1966 unit number: not found

You mention 1966 is 100001. Since I do not find info for 1966, we must extrapolate from 1964.
All is good, just trying to get it all correct. thanks for your expertise. Feel free to correct the above. I am starting to get data overload. (that's what we older guys like to call senile). Doesn't take much now-a-days.


Right is right, even if everyone is against it, and wrong is wrong, even if everyone is for it. - William Penn