If you're putting a block on the graphics card it will need specific thickness pads. All the EK ones I've put on come with what they need and it's a mix of 1 and half mm pads.
If it doesn't come supplied with them, it at least ought to specify in the destructions, surely?!
There's normally (on the EK blocks at least) thermal paste on the GPU die and the RAM and VRMs are pads. It could be that your block is GPU only and doesn't cover the RAM and VRMs. In that case, you need heatsinks for those.