It's the right cartridge and the right box, and the instruction manual looks right. But inside said manual, although the illustrations are Lion King, the instructions themselves are for playing GT Advance 2 Rally Race.
Which is kind of a shame, because the idea of taking Simba for a lap or two at Monaco is very appealing.
Furthermore, judging by the screenshots on the back of the box the game itself is no more than a rehash of The Lion King: Simba's Mighty Adventure for Game Boy Color, which in turn was the plain old Lion King for Game Boy original with a couple of extra levels.
Can't blame my seller for that, though - that's just bastard Disney and their policy of turning maximus bonus cum minimo cliparte 1.
First person to say "oh well, hakuna matata" will die horribly in mysterious circumstances.
1 'The greatest profit with the least amount of clipart'. The last word doesn't end in -o because I arbitrarily decided 'clipart' belonged in the Third Declension.