En mobileread han contado esto:

The serial number can tell you. In this, 7th character of the serial number will be a 0 for the first version and 2 for the updated version. To identify them when connected, the product id of 378 is for the Aura H2O Edition 2 Version 2 and 379 for the Aura Edition 2 Version 2. In the USB identifiers, the value of BCD has changed to "0x401".

Básicamente hay que mirar la séptima cifra del número de serie del aparato. Si es un 0, es la ed2 v1 y si es un 2 es la ed2 v2.