Nintendo 3DS Pirated Carts?

[Games Retrospect]

I got a 3DS XL a few days ago for about half the usual price and I'm super happy with my purchase. Thing is, I have no games to play on the console yet. I was looking to buy some games online and found a store that sells used 3DS Pokemon games for not that much money. I really want to play those games, but I also want them for my collection. Since the asking price wasn't that high I asked if the carts were pirated and the guy said 3DS pirated carts don't exist. Has anyone here had any experience with pirated carts on the 3DS? If they do exist, how do I spot them? Will Metal Jesus' video guide to detect them will work for 3DS games or only for DS ones? I can ask for pictures of the carts and I can post them here if you want, but I really don't want to spend my hard earned money on something that's going to look really bad on my collection.