Those are smaller than you indicate by 10x. 13mm not 130mm. They may be good as one per chip but they wouldn't work for the whole board (obviously). There's a lot of these RAM/VGA chip coolers out there. They may work per chip but once you add them up you end up spending more than one big heat sink. (I'm looking for a nice blue cool looking one for the K1 however, about 1"x1.25").
"Effy Deal Global" - with a name like that I hope they're not real. But who knows.
The price doesn't surprise me at all. I'm expecting to pay $2.70 each in qty 100.
On the heatsink question, I do have one concern on the center of the K64 or wherever two or more K64s share an edge (e.g. "K256"). That's centralizing a lot of heat in comparison. Just wanted to bring the topic up so that whatever heatsink selected/recommended they allow for a clear airflow path when they are placed side-by-side.