Unfortunately as a day one player, I had no choice but to delete day one weapons as I had no vault space left when TBD dropped. That and the continual weapon nerfs, and no indication what so ever they were going to introduce the upgrading of older legendaries at the time meant their was no point in keeping the original guns. It's very easy to say now, nearly a year from release to not delete those guns, but a lot of us at the time didn't have any choice.