To find out whether it's a pre-production unit, simply check the firmware: menu > settings . about device: If you have version 1.2009.42.somemorenumbers then it's a production unit. The '42' guarantess it's the production firmware, not an early one.

The 'Not for sale' is probably because they have a bunch of them in various Nokia locations and it's to stop satff sneaking then out and putting them on ebay. Same as kellogs variety packs say 'not for individual sale'.