As per 19.2.8, A helicopter must fire all its weapons in the same impulse. Helicopters with both machine guns and ordnance can fire these weapons at targets in different hexes only when they are in flying mode; when hovering a chopper must fire all of its weapons at targets in the same hex.
That being said, since the Huey gunship is marked 2x, it can fire twice but in the same impulse as per 15.0 If “N x” precedes the HE-equivalent, “N” is the number of times the vehicle’s main ordnance can fire in its impulse. A vehicle that can fire its main gun more than once can fire its gun at more than one target in the same impulse but the targets must be in the same hex or an adjacent hex.