This is just educated guessing on my part, but I think it's silver because he has coated it all in solder then polished up the solder, (study the other images in the picture linked topic).
The effect is nice but let down a little by areas of the base plate being left with copper showing through.
On all the 3d cards I've owned there is a difference in height between the Ram & VPU/GPU. It differs from card to card depending on Ram type, VPU/GPU type, and card design, on the 9800 pro it's around about 1mm
I'm making a cooler atm
had a 9800 pro for a while just been side tracked by other things:-
here's where I'm at.