A resposta é nenhuma , isto é, a menos que seu GM decida adicioná-la a um grupo (veja abaixo). Do PRD (Core Rulebook):
Weapon groups are defined as follows (GMs may add other weapons to these groups, or add entirely new groups):
Axes: battleaxe, dwarven waraxe, greataxe, handaxe, heavy pick, light pick, orc double axe, and throwing axe.
Blades, Heavy: bastard sword, elven curve blade, falchion, greatsword, longsword, scimitar, scythe, and two-bladed sword.
Blades, Light: dagger, kama, kukri, rapier, sickle, starknife, and short sword.
Bows: composite longbow, composite shortbow, longbow, and shortbow.
Close: gauntlet, heavy shield, light shield, punching dagger, sap, spiked armor, spiked gauntlet, spiked shield, and unarmed strike.
Crossbows: hand crossbow, heavy crossbow, light crossbow, heavy repeating crossbow, and light repeating crossbow.
Double: dire flail, dwarven urgrosh, gnome hooked hammer, orc double axe, quarterstaff, and two-bladed sword.
Flails: dire flail, flail, heavy flail, morningstar, nunchaku, spiked chain, and whip.
Hammers: club, greatclub, heavy mace, light hammer, light mace, and warhammer.
Monk: kama, nunchaku, quarterstaff, sai, shuriken, siangham, and unarmed strike.
Natural: unarmed strike and all natural weapons, such as bite, claw, gore, tail, and wing.
Pole Arms: glaive, guisarme, halberd, and ranseur.
Spears: javelin, lance, longspear, shortspear, spear, and trident.
Thrown: blowgun, bolas, club, dagger, dart, halfling sling staff, javelin, light hammer, net, shortspear, shuriken, sling, spear, starknife, throwing axe, and trident.
Nesta lista não há entrada para a pistola de cana espada, o que significa que o bônus de +1 não pode ser adicionado.
No entanto, se seu GM adicionar a pistola de cana em um dos grupos, você ganharia um bônus em todas as jogadas de arma, como se fosse um quarterstaff.
EDITAR:
No entanto, se você estiver usando o livro de regras Ultimate Combat, você receberá o bônus.