I just purchased a new Polaris 3900. After getting it home I noticed a lot of dust on the box and the unit was also a little dusty ,it was a sealed box. after opening it I noticed the tail sweep didn't have the newer tail sweep end. I called Polaris and asked them about that and they told me that the unit was manufacture in March of 2011.I has guess it has been sitting in a warehouse. The Polaris tech wasn't that much help. Have there been any updates to the 3900 since March of 2011? should I return and ask for a newer unit?