Hi there, the 100% sure way to tell is to open up your GPU, and compare the PCB. You don't want to go through the trouble of Refunding your waterblock if its the wrong one.
Does your card have a backplate?
Does your card have a Bios Switch?
There are different components on Ref and Non-Ref cards, that will interfere with your waterblock if you buy the wrong one.
I myself, Have an HIS Radeon 6970 too, like the one you linked. I got mine from newegg, and mine isn't reference, its the version 2 revised one.
Basically, the V2 and Ref have the same Model Number, so Newegg didn't know if they shipped you a Ref, or v2 card. Im not sure if its like this for Amazon.
For Waterblocks, EK makes both Ref and Non-ref 6970 Cards. http://www.frozencpu.com/cat/l3/g/c3...cks-Page1.html
Keep in mind there are other sites, im just linking a good online-store so you can look at it.
Good stores: Jab-tech, Performance PCs, Frozen CPU, Side winders PCs, Aquatuning.us.
This reference block is acetal (Black-ish) http://www.frozencpu.com/products/12...=c309s1373b133
For Non-ref, EK has blocks, also DangerDen has a v2 one. "6970-6950 Wateblock v2"Edited by Nynn - 10/20/11 at 9:20pm