For the 2010 release, you will get a 2010 serial number.
When Softimage 2010 is released, the download version will probably be available a couple of days before the physical shipments go out. So customers on Subscription can go to the Subscription Center to download 2010 and get their 2010 serial numbers.
When the physical shipments go out, you’ll get an e-mail notification that includes your 2010 serial number. The 2010 box will also include your serial number.