Generally, positive on coil goes to battery. In practice it really doesn't matter because the coil is only a load. When the points open it causes the voltage in the primary coil windings to collapse across the secondary windings and create a voltage surge, also called a spark jump. The only consideration is that the secondary windings MUST be attached at the + terminal of the coil.(This would be an internal feature of the coil.) The other end of the secondary winding goes to the spark plug, of course.
Let me back up on this and say that the primary windings(low voltage), and secondary windings (high voltage) are always joined to the negative coil terminal going to the points. The positive terminal still goes to the battery (or ignition switch).
Lol. Thank you Don. I spent yesterday reading a forum arguing about which one went to the battery and after 50 or so posts... it still wasn't clear what was correct. I will run the positive lead to the battery then.