Aran's guns are named Shock and Striker whilst Rundas' are named Frost and Shatter, and are in fact made using bones from whatever matter of literally hellish beings made the unfortunate decision to attack these lynx demons :3
The white-boned guns, Shock and Frost, are better suited to inflicting elemental damage to weaken targets, while their darker-boned siblings, Striker and Shatter, were built for raw damage output. And yes, they are fully ambidextrous (not that they even have anything on the sides that would need to be mirrored for that)