I'm not sure, but in the case of the fancy pant babies, there where two "sets" the one sold in the USA and the one sold in Europe. One was made in China (sold in Europe) and the other I think it was Thailand and sold in the USA.
They are difference in the ponies: eyes, length of mane and tail...
Maybe something similar happens with this set? In Spain we only got 4 of the 6 Sweetberry Ponies: Strawberry Surprise, Boysenberry Pie, Cerecita and Mermelada (sorry, those last two I don't know the names in english).
I guess they used different materials in each factory and that is why there can be differences.