Keyspace List for WPA on Default Routers

[zarabatana]

Here in Brazil we have an ISP called GVT.
The default password is the Serial Number of the wireless router.
Here is an example:

D-Link
SSID: GVT-8A8A
PASS: N1B9027544
SERIAL: PJ2N1B9027544
MAC: 84:C9:B2:EB:8A:8A

Just count 10 chars from right to left, and that is the WPA/WPA2 Key.
My question is: there is a way to calculate the Serial Number?
D-link was used in this example, but, it can be Arcadyan, Sagemcom, etc. It always will be the Serial Number.
Using wireshark, the serial number received isn't the same in the stick on the bottom.
Thank you for your time.