What does a z in the VIN number mean Im looking at 2 trucks both are the same one has a z in the number one has an m?

Toyota VINs starting with "1", "4", or "5" represent vehicles assembled in the United States and VINs beginning with "2" indicate vehicles assembled in Canada. Vehicles with VINs that start with "J" were produced in Japan. The next five digits (4 through 8) are the Vehicle Description Section (VDS). These digits provide information on the vehicle model, body style, and engine type. The ninth digit is a check digit used internally. The 10th digit indicates the model year; letters (except "O" and "Z") were used for vehicles up to the 2000 model year while numbers are used for 2001 and newer vehicles. For example, "X" means the 1999 model year, "Y" is the 2000 model year and "1" represents the 2001 model year. The 11th digit is the plant code. Finally, digits 12 - 17 are the unique serial number.