Just like the engine, the factory painted the air cleaners all at once after they were assembled. So the pods got the same paint as the rest of the air cleaner.

The pods were held on with little bent metal tabs--put on before paint.
If they would have tried to assemble them after paint, the paint would have all flaked off and would have been much harder to assemble that way.

Don't believe me check out the later 73 air cleaner that was orange. Pods were also orange--painted all at once.