Yesterday I had two weapons in my items box which had no charge (power = 0) with them.
One was a Double-Barreled Rocket launcher (level 28 rare) - unfortunately I already fused it, so I am a bit unsure about the name.
The other one was an Apocalypse Mark III (level 30 legendary shoulder gun) which also had a power of 0. The other items I got had correct values (half filled level 1).
I know about dual barreled rocket launcer, and you're right about it. some certain weapons start with no power within them, i don't know the reason though...
Weapons I've received from items boxes that come with 0 charge: 'Dual Barreled Rocket Launcher' (level 29 rare), Missile Battery Mark II(2) (level 28 epic), Missile Battery Mark III(3) (level 30 epic) 'Iron Shredder' (level 28 legendary), 'Iron Shredder' (level 30 legendary), and the Apocalypse Mark III (3) (level 30 legendary).
I guess it would be hard to go back & give these items power but if you could bring back the option to sell these items in the market it would be appreciated. I have about 18 of these items just sitting in the inventory with NOTHING to do with them.