Not as far as I can tell. All I've ever had drop is Jolder's Hammer (2 of them) and Timur's Lash (4 of them). Further more, there is no gameplay footage of them anywhere, while there is a decent amount for the currently available weapons. I think that the other weapons, which are a Sniper Rifle, Auto Rifle, Shotgun and Rocket Launcher, will be released during a later rendition of the Iron Banner.