Hi Muf,
As owner of one of the 2 Coupes listed in the Registry, I've tried to learn all I could about the Coupe. I have not found any examples of the car you are looking for. In 1967, with the introduction of the 250SL, a "2+2" or Coupe was made available and has a fold-down rear bench seat. Ford had introduced the 2+2 concept and I think this was a response to that.
My only guess is that if someone ordered a 230 without a soft top, it would simply have been a roadster without the soft top installed much like John describes his "option 415". My Coupe is 417.
And, I find my car quite practical for Florida. I love the Pagoda roof and prefer to leave it on. My A/C works great. On the days when I do drive it topless, the fold down seat makes a great platform for my dogs to ride upon. I have harnesses that I attach to the seat belts and they can sit up high enough to enjoy the view. That always attracts approving smiles from the ladies.