It's much more likely to damage the points than the coil. If the distributor stops with the points closed and the switch is left on, there will be a constant flow of 5 amps or less across the points. The coil primary windings can take it, but that's enough to overheat the points and burn them sometimes. To check for excessive point resistance, turn the ignition switch on, bump the starter until the points close, and measure the voltage from the (-) coil terminal to ground. It should be less than 0.25 volts. Any more, and you'll need to clean or replace the points. What the voltmeter is reading is the voltage needed to force the primary current through the point contacts, which should be virtually zero.
Jerry
