I definately have the '68 ball stud bracket as shown in your post. I really don't know for sure what year the bell housing is. It came with the engine in the car. The VIN on the engine matches the transmission and the dash, so I doubt that it was ever changed for something different.
I had exactly the same issue with my 71 Demon. The PO had a 72 and up bel housing on the car. As soon as I put the 71 and earlier (2892-482) bell housing on, everything lined up the way it should be.