https://www.gamespot.com/articles/most-of-destiny-2s-new-faction-rally-weapons-arent/1100-6456171/

Destiny 2's latest Faction Rally event is a significant one, as it is the first to take place since Season 2 kicked off with the release of the Curse of Osiris DLC expansion. As a result, it features the addition of new gear and items for players to get their hands on, but it turns out that exactly what can be obtained right now isn't what players had assumed.