you can test the coil by making sure everything else works, i mean see if there's power coming outta the stator, just holding the wire while turning the flywheel with a drill or whatever. if not, it's likely points, maybe a short. but if that does spark double check the other wires to the coild are disconnecter - what i mean is remove the wires goin up to the switches. just bypass that for troubleshooting . check spark and if nada, try just the bare plug wire (eliminating the plug uitself and the boot to check if those were the fault. at this point you've chased back from both ends and can be pretty confident it'd be a coil problem.
Alternately you can test the coil itself. grab a battery of the same voltage as the bike (that year for sure oughtta be 6v) and you hold the coil and plug in hand, with the coil and spark plug grounded to the negative, tap the power in lead for the coil against the positive terminal and it should pop a lil spark. just a wuick jump every time you tap it.