They never had any banners for the first two championships until last year. They only had their 75 championship banner. But when NBA added 3x champions on their jerseys. To not make that confusing they added the first two banners absent of any NA imagery. The few franchises that had won NBA titles in other cities are now starting to recognize those championships, especially with the recent addition of the gold tab on NBA jerseys with all of the franchise championships. In addition to the Warriors, the Kings had also put up a banner recognizing their only title in Rochester. The Atlanta Hawks just last week put up new banners, including a banner for their 1958 championship, and retired numbers.