From what I can tell this is a fake. Take a look at the Nintendo logo on the backside of the cart for example, original carts have a small circle above the o on the right side and the font looks wrong too. If that's no enough proof take a look at the first four letters of the code below the...
btw i feel this a good time to remind you guys that sea of thieves was made by rare, who also made DKC1-3 and DK64, alongside banjo kazooie and conker's bad fur day