It's pretty tough from what I remember reading.
You have to peek inside through the holes to see if there is an extra chip attatched to the fan wires.
Turn it on, and see if the fan turns on right away, or if it waits a bit before turning on.
I'm sure if you e-mail the Novak guys at firstname.lastname@example.org
- if there is any other way to tell the difference, they'd know it.