67 doors will not fit because the Cab is slightly different- besides the doors, the back glass on the 67 is noticably smaller. If you have rear leaf springs on the 4x4, the 72 may or may not have them as they came with both leaf and coil. I don't know it this determines the brakes. If the 72 is a cheyenne you should be good to go as they have leafs. The door panels might not be exactly the same, but you can buy aftermarket on just about anything too. all the windows/locks, etc are the same. Many GMC parts will work too, but not the grill/radiator support, as the GMC had 4 headlights. everything else will interchange 68-72. For aftermarket, try bowtiebits.com - it is located in Wichita Ks.

check L M C parts catalog, you can get a lot of information about your truck from their parts catalog, www.LMCtruck.com is their web site. good luck, mercnut.