There is a foreign variation to this sword out there. Some European swords look very similar to this and do not light up! If you get one from a European country make sure you are getting the light up version!
There are certain things to look out for when buying a Sword of omens toy:
Sword blade:
The swords are packaged by being fixed to a card with two plastic tags. Some swords were packaged with the tag running over the blade and therefore making a dint across it from the pressure of the tag. This did not affect all swords though as my MOC sword has the tag running just below the hilt (see pics at bottom of page)
Eye of Thundera symbol:
The black paint on the Eye of Thundera symbol wears off very easily and some loose swords I have seen look pretty bad. Try to get a sword with minimal paint loss, but don't be too picky as this is a very rare toy!
Battery compartment:
Most loose Sword of Omens no longer light up. This can be caused by damage to the metal battery connectors inside the sword (see pic below)
Battery cap:
This part is most commonly found missing from a loose sword. It is very important because without it the sword will not light up. Most people are looking for this part to complete a loose sword so this part is very very rare!
Next to the Cats lair and Tongue-a-Sauras, the Sword of Omens MOC can be very difficult to find as it's a very rare piece. Especially on an English card. Below are pictures of my MOC sword. The sword is on a very rare American card!