I hope you are correct for the poster's sake. The change that your picture described was the addition of an additional separating chamber in the splash bowl located in in the sump of the tank to stop gurgling as a result of vapor being returned with return fuel. The original tanks also had a splash bowl in the sump to provide a steady fuel flow when cornering with low fuel. The piping located at the inside top of the fuel tank is to provide a method to separate the fuel in the tank from the fuel vapors that had to be vented above the design pressure. All MB tanks from other models of the era had external expansion tanks to catch overflow and separate the liquid from the vapor. I seriously doubt that pipe 71 in the later fuel tank diagram exits the tank from the top without some mechanism to separate liquid from vapor. Of course this could be definitively demonstrated if tinypanzer would cut his tank apart for us Mark