Just about any dual output coil with 1.5 ohms of primary resistance will work, as long as it fits in the space of the original coil and doesn't chafe on the fuel tank .
My '84 LS came with a non-stock coil, it has no identifying marks on it as to who the manufacturer was .
It is a round coil like a Bosch coil, but it is about half the size .
From what I can tell by the maintenance log I got with the bike, it had been on the bike since 1987 .
A lot of work went into making that coil work on the bike, a lot more work than I would have put into it .
The previous owner wasn't very good at troubleshooting, the bike developed an ignition problem, the first part he replaced was the electronic 'bean can', then the ICU, finally realized that the coil was bad, I got the old coil in the boxes o' parts that came with the bike, as usual, the case was all cracked in multiple places .