Nope, the F-2 has a 15mm in the nose and two 7.92mm machine guns above the engine, but the F-4 and G-2 both have a 20mm cannon in the nose and two synchronized 7.92mm machine guns above the engine...
I'm not sure it would. The single tail probably offered a greater surface area. It's interesting to note that some of the last versions of the B-24, the PB4Y2 and the B-24N featured a single tail in place of the twin fins of the earlier models.