Originally there was a square shaped head on the inside of the distributor where the point spring and condenser went. This bolt passed through the distributor body and on the other side was a round nut that had two slots in it that tightened the point spring and condenser wire up as it tightened against the body. Then the wire from the coil went on top of the nut and another regular hex nut used to tighten the coil wire to the stud left sticking out.

Sounds like someone changed the stud that is supposed to be there out for a regular screw to me.

I think I may have an old distributor here with the correct bolt/stud to use. Maybe I can get a picture of it and send it so you can see what it looks like. But it will be later today.