I do not believe the clutch fan was available (not enough clearance). There are two part numbers for the clutchless fan blade you are looking for. One for AC and one without AC. I just saw them online yesterday. I'll ping you when I find the web page again.
For the 1967 the part numbers where 2863203 and 2863202. I was mistaken, AC is not the differentiator, California is. The California cars used the 286202 part number. I have no idea what the difference was.
I know you are inquiring about a 1968, I don't have a 1968 parts manual. I would be surprised if they were different.