[GMCPaul]

1967 bed sides mounting holes are Exactly the same as 1968-72 bed side mounting holes. The only difference between 1967 & 1968-72 is there are No side marker light openings on the 1967 bed sides, otherwise it is exactly the same.
In regards to the front clip everyone's correct you will need to replace the entire front clip to use 67 front fenders and have them just bolt up without modifications required. Now you could modify the leading edge of the front fender on the 1967 fenders so that the 69-70 grille will fit over the front edge of the 67 fenders but it would be far easier just to cut out the opening for side marker lights on your 69-72 front fenders and then weld the opening shut to delete the side markers. Far easier than trying to modifying the leading edge of the 67 fender or grafting the leading edge of a 69-72 fender onto a 1967 fender to make it work in order to get the 69-70 grille to fit over it like it does on the 69-72 Chevy.
Paul Jr @ GMCPauls