Currently there are 6 "Gunweapon" models in game (excluding the Blazefire saber), a generic gunblade (used by ranking Garlean troops), the gunblade Heirsbane/No. IX (wielded by Gaius van Baelsar), the gunshields Tartarus (dual wielded by Rhitahtyn sas Arvina), the gunhalberd* Bradamante (formerly used by Nael van Darnus), the gunbaghnakhs Algea (used by Livia sas Junius) and the gunhammer Mjolnir (used by Nero tol Scaeva).

As of right now they have the models to arm the Gladiator with a gunblade and gunshield, the marauder with a gunhammer, the pugilist with gunbaghnaks and the Lancer with a gunhalberd. They may just be wait for the right time or trying to figure out a way to give them trigger actions to make them feel like gunweapons.

*Bradamante is interesting because it seems to be currently in the hands of a infamous weapons collector and may be one of the rewards for completing a battle on a big bridge.