I think It's different from the GAN330.Is GAN328 a slightly smaller GAN330?
GAN330 sale as a single product and has a hole for a keychain.
GAN328 sells as a bundle but doesn't have a hole on the cube. It comes with a white plate as a bottom which has a hole and a stand for display on the table/ wall. Additional magnets on the white plate side to combine with another cube set.
Hope it's help~