I'll check the plug wires themselves (I had labeled them according to the coil numbers), but when I install the Delco unit, I'll set it up how it should be. It had always ran on all cylinders, though.
Edit: After looking at pictures of the Magnavox-style ICM, it seems there's spades that get hooked up to the coils and then sandwiched between the two, so I suppose it's possible it was wired correctly, and simply installed upside down. I could take a look at it later, but this seems like the most likely cause.