It actually came with two boxed pokemon games. Both are in Japanese, so I can't test how well they work too easily.
One cartridge shell is warped. They both say "Nintendo Gameboy" on them which is somewhat uncommon for a pirate. (keyword: somewhat). The two pieces of the shell are different colors, which is neat. The front is a blue-ish purple, and the back is grey, and vice versa on the other one.
Those actually might be legit, then. The real Japanese Pokémon G/S carts were exactly like you said.
I have a pirated copy of Crystal. HILARIOUS. (It's a cartridge copy of the one floating around the internet)