Complex sentence: The final 1,560 SJ Grand Wagoneers were produced in the 1991 model year, though it appears that four individual vehicles were produced as 1992 models to fulfill existing orders.
Split into simpler sentences: The final 1,560 SJ Grand Wagoneers were produced in the 1991 model year. A number of vehicles may have been produced as 1992 models to fulfill existing orders.