The only replacement bulbs I see on there are for Road Star and HD bikes (not surprising ). There is, however, a complete 5 3/4 inch headlight assembly that would probably be able to be used on any BA/SM, provided you're willing to part with almost $500. Heres a link

Yes, I know this is not Kuryakyns website, but the only thing they seemed to have was the replacement bulb for the Road Star.

Thunderpipes, 135 mains, TBS needles, snorkel & AI removed