Rfguy,
The plastic balls in the tank vents are no longer used on the 430, and as far as I know the the 230 either.
They were added to get the 160 certified was the advice I was given from the factory.
There should also be a vent from the header tank to both wings. The header tank should have 3 lines each side, two feeds and one vent.
The construction manuals are very good, but there are subtle differences and improvements that haven't been added over time.
Mike