Yay or nay?

Nay, the DLC isn't about Sebastian, and Juli doesn't have Sebastian's weapons.

Please devs, could you make that on DLC New game + we can access weapons?

So, on first playthrough you will be without gun, on second with gun.

Thanks

The Assignment is not designed for combat. This simply would not work.

However, I have heard rumours that The Consequence will feature gunplay.