When you look at the engine of a 400E or an E55, there are two hoses providing air to the top of the engine. Each getting air generally on both sides of the radiator.
On a 1997 E420, there is only one hose providing air from the right side of the radiator. I am getting my information from looking at my car and pictures of the engine bay of the 400E and E55. For that matter, I believe the S420 also had two air intake hoses. Did that answer your question?