What is the first year gmc/chevy used the third door on full size trucks?

What was the first year gmc/chevy started using the third door on the full size trucks?|||1997 was the first year when chevy and gmc ex cab trucks started with the third door.Best of luck.|||1997 was the first year. It was an option.





In 1998 I believe that it was standard.





The 4th door was not available on the OBS trucks. It was avail on the NBS '99+ trucks.