I believe I've seen a post indicating they were branded "Electroline" and came on LaFrance Fire Trucks. More info in this post http://www.jalopyjournal.com/forum/showthread.php?t=450673 &highlight=lafrance+headlights
Yep, They are electrline and they did come on firetruck and other early commercial vehicles. VERY PRICEY $$$$$$$$. http://www.jalopyjournal.com/forum/showthread.php?t=276071