Better chance of hitting? Sure. 4000 rounds means more chance of hitting, yes.
Better chance of hurting? God, no. 2x 50cal are 50% more efective than 4x 30cal. That's how sad and weak the 30cals are. Can you get kills? Sure. In the same effort it took you'd have got 2x as many kills with the 50cal option.
That's not an opinion. It's a fact based on how the guns are modeled. You might have a preference for weaker armament, but doesn't make it a better option.
Also, there'd be no weight difference. The empty weight would be the same, and the 4x30cal gun option would weigh about 200lbs more than the more powerful 50cal option. US pilots actually welcomed the 50cal gunpods (even though Soviets removed the wing guns to save weight).