remember this, random acts of kindness are not often, but next time you get stuck in a situation of injustice, or have the ability to grant someone else kindness they dont deserve, remember what this seller did for you this time.
You don't really have to crack those open to check them for legitimacy - most require just tilting it and having a look at the connectors. Nintendo games have a faintly visible, white Nintendo logo right above the connectors if I recall correctly...
...and then there's the fabled Nintendo screw that was the bane of many collector's existence (gotta love changing batteries with proprietary tools), but at the same time a blessing as most counterfeit games either used normal screws or were downright glued shut. Of course if you have the right tool for the job, it's okay to double-check.
Yes, there are some downright triangular screws out there. The sheer amount of proprietary screw heads out there has my head scratching. Honestly, the human race should just agree on one type instead of expanding people's toolboxes lol.