3rd door was an OPTION in 1997, and was standard in '98+ ON 1500 SERIES MODELS. I have NEVER seen an 2500/3500 series truck with a 3rd door older than a 2001.
Front seats were the 60/40 split with fold up console to hold a 3rd person, captains chairs with fixed center console mounted to floor, and the bench seat. The 60/40 can have powered drivers as well as the captains.