Instructions
Look at the R4DS package. If it doesn't have the "Micro SD" logo in the bottom right corner, the R4DS is a fake.
Check for a sticker on the package indicating the storage capacity of the card. If the package has this sticker, the card inside is a fake.
Look at the R4DS card itself for a sticker that indicates the storage capacity. Real R4DS cards do not have a sticker indicating their storage capacity.
Feel the card. If it seems flimsy or poorly built, it may be a fake.