This is the most frustrating part for owners. Unlike cars (VIN decoding) or modern tractors, Deere treated the 7000 as a "toolbar with parts." When you call a dealer with a 1979 serial number, their system often pulls up the same parts diagram as a 1982 model.
You will find third-party websites claiming to decode 7000 serial numbers instantly. Most are inaccurate. They often blend tractor serial number logic with implement logic. Here is a real-world warning: John Deere 7000 Planter Serial Number Year Of Manufacture