Did they make such a thing from the factory?
No, when you see a truck that old with four doors it was build by some coach builder or customizer. There used to be quite a few companies building that kind of thing for commercial use.
The first factory built GM crew cab was the '73 3+3 or Bonus Cab.
I used to see one around here all the time and I told the owner when he was done with it I wanted it. I was going to use parts of it on one of my projects. I haven't seen it in a long time so it may be gone.
