I think it depends on the fighter model (first production, last production?!). Performance could be the same, horsepower could be different but firepower should be different.
F4U:
-Maximum speed: 446 mph (717 km/h)
-Service ceiling: 41,500 ft (12,649 m)
-Rate of climb: 3,100 ft/min (945 m/min)
Armament
-6x .50 cal Browning M2 machine guns (F4U-4) or
-4x 20mm Hispano cannon (F4U-4B or C)
F6F:
-Maximum speed: 376 mph (612 km/h)
-Service ceiling: 37,300 ft (11,369 m)
-Rate of climb: 3500 ft/min (1067 m/min)
Armament
- 6x .50 cal Browning M2 machineguns