We should be able to reacquire weapons and better rolls, customizable rolls through the gunsmith. As you rank up you unlock better rolls say every 5-10 ranks including sights for the weapons. That means you would have to grind for the God roll but once you do obtain it you can reacquire it. Rng can still be in the game but if you delete the God roll without having a high gunsmith rank you're screwed until you level it up.