To my knowledge, desert box turtles usually have greenish heads and a lot of fine yellow radiating lines on the shell whereas ornates usually have a brown head and thicker, less numerous yellow lines.
The desert race (ornata luteola) typically has 11-14 narrow lines present on the second costal scute. Ornata ornata usually has 8-11. If you post a picture we can help you ID him.
Note luteola and ornata are subspecies not races. A race has less genetic differences then a subspecies. Some examples are Boa constrictor imperator is a subspecies of Boa constrictor where as the Columbian Red tail Boa is a race of Boa constrictor imperator as is the Mexican Boa.
pictures may help the number of lines as posted above is probibly the best bet, although the (green head) thing is wrong as many male ornates have a greeeeeeene head