To retrieve information about a Nokia mobile firmware, you can enter the *#0000# code from the phone main screen.

This will popup a small window which will give you three informations:
  the firmware version number (V2.50 for my 3650)
  the firmware release date (12-02-2003)
  the Nokia product model code (NHL-8 for a 3650)

A list of Nokia product codes is available here.

I don’t know how non-Nokia devices based on NS60 (SX1, SGH-D700) will react. You can also note that this key sequence should turn the phone into its default language settings as specified by DCS Phase II specification - which is not the case on Nokia handsets.