Primetimeups

Hi, does anyone know if I need to change the wiring from my 2002 4.2 body in the back from the 2008 4.2 (which was loaded Heated seats, Leather etc) . The plugs some of are there like for the Bose, the heated seats the seat belt are not like when buckled on the 2008 wiring tot he old 2002. I changed the body from my 02 to the driveling on the 2008 because it was a roll over. I did do the wiring harness in the front to the computer and all the dash with the new Radio and heat A/C control module. I was wondering if I could just leave the old in or should I put the 2008 harness in from the doors to the BCM tot he back hatch and the other side (passenger). This is hard to write so bear with me. The plugs to the doors are the same and a lot of other just the seats the bose and few others I'm not sure of. Thank you.