Do doors and fenders interchange
 

Will the doors and fenders from a 69-72 truck fit a67-68 truck ?

Re: Do doors and fenders interchange
 

The doors will all bolt up. The 1972 doors you will need to use the 72 only door panels unless you make some slight modifications.
69-72 GMC fenders are te esame as your 67/68 fenders, 69-72 fenders are not the same and will not work. The 69-72 Chevy fenders will bolt up just fine but the front of them has a large indentation for the Chevy grille.

Edit: here are pictures of the two styles of fenders. The top one is the 68 Chevy/GMC or the 69-72 GMC style. The next one is the 69-72 Chevy style. You can see how the front of the fender is different.