It's not strictly sequential, but it is easily guessed if not sequential. The first portion is manufacturer's information, and then the last 6 are a serial numb

It's not strictly sequential, but it is easily guessed if not sequential. The first portion is manufacturer's information, and then the last 6 are a serial number of final assembly (generally speaking) VIN Card [big pdf]: https://www.genuinegmparts.com/src/pdf/resources/1960-2020_Vincards.pdf https://www.genuinegmparts.com/src/pdf/resources/1960-2020_V...