Fake pokemon DS Game?

Hello,

I need your help with a Pokemon Soulsilver game which i bought on ebay.

Sadly I fear it‘s a fake but I‘m not sure.

The serial number on the front doesn‘t match the one on the back.

Is that a sure sign?

Greets

https://imgur.com/gallery/Pap9h

One's for the case, the other is for the sticker, its normal.