Started a new run with an endless chest and got an uncommon Sparkler that has exactly the same values as the common version listed in the Workshop (including an incorrectly calculated DPS, but displaying the correct Elemental Power in contrast to the Workshop). The other weapon, an uncommon Boomstick, had a +30 % Damage Bonus. I don’t think this is connected to it being a starting chest as I’ve seen similar things mid-run as well.