[Bigdav160]

Finding a hatch that isn't rotted completely out is near impossible. I haven't seen one for sale in years. No reproduction pieces either.

When I purchased my Suburban (from California) the hatch didn't have any external rust. I thought I had dodged a bullet. Within a couple years it was a mess. The metal is unfinished on the inside. Water gets by the hinge grommets. Disassembly of the hatch halves is not easy. There are hundreds of spot welds in the seams. This is where the metal will be very thin due to the rust.

If you search I think you might find some differences in the sill between barn doors and tail gate.

Mine wasn't a 3 seat truck but I added one. I purchased the proper frame mount from a member on the board. I took a folding third seat from a mid 70's Blazer and modified the upper corners of the seat frame to give the rounded look of 67-72. The foam and seat cover for a '72 completed the look.

I can't answer about the grill. I would assume the grill and inserts are unique to each other and 67-68 sloped nose are completely different and don't interchange without matching fenders, core support and hood.