Seraph weapons sound like great guns, but I don't have the Captain Scarlett DLC. On the other side, I've got a few friends who does. Will I be able to exchange Seraph weapons with them (either by trading or simply dumping it on the floor) ?
I think that should be prety clear. If you don't own the DLC, you aren't able to use the weapons that are introduced in that DLC. This was the same case for Borderlands as well.