Most modern ignition coils have a + plus and a minus - marking for the primary terminals. Polarity can be mysterious sometimes but coil polarity testers are are available to make sure it has proper spark. The later coils were connected +plus to the ignition switch power and -minus to the distributor points but they are all negative ground systems. In the positive ground era the -minus would be connected to power and the +plus would be connected to the distributor points but as I mentioned this doesn't always give correct polarity.
This is a link to one of the model A wiring diagrams on Vince's site.
http://www.fordgarage.com/pages/awiringdiagram.htm
It appears to be the last version.
The standard on/off type switch would be wired in similar fashion but no Electrolock.