All windscreens from 2001 thru 2010 are interchangeable (with or without the vent), and the 2012 windscreen looks just like the others, except it is made by a different supplier. So, my guess is that the 2012 and 2001 are interchangeable. However, the part numbers may be different for a couple of reasons:
The 2001 doesn't have a vent and the 2004-2012 do; and
The 2012 Windscreen is from a different supplier than the 2004-2010;
We won't know for sure until someone makes an actual swap.