Now that I think about it, the dark below and house of wolves were both considered expansions by Bungie. So if we didn't have to get rid of our guns for those expansions, then I don't see why we have to now. They even made a system for us to upgrade our old weapons with the house of wolves expansion. Like I said, they're really confusing people and many think TTK is Destiny 2. If so, then we should have to forget our old guns. But I f it's just another expansion, the we have the right to keep them. https://www.destinythegame.com/content/dam/atvi/bungie/dtg/editions/items/expansion-pass.jpg