Difference between Bf 110G-2 and G-4

[Pete63]

Hello, everyone.

This is a question for the Messerschmitt Bf 110 experts:

What exactly is the difference between a G-2 and a G-4..? I’m not an expert on these Messerschmitts, but I’ve stumbled upon aircraft with small rudders and trimtabs that seem to be G-2 aircraft and the ones with the larger rudders and trimtabs seem to be G-4 aircraft.
Or is any G-2 equipped with FuG202 radar antennae automatically a G-4..?

I’m a bit in the blind here. Are there any Werknummer listings..?
Could one say that e.g. W.Nr.5302 is a certain subtype by looking up the Werknummer as such..?
Hopefully someone can help me with this.

With kind regards,
Piet Bouma
The Netherlands