noludoru--
Borzoi coats can be tricky because the shading of the hair changes as the pups age and because the length and backbrushing of the coat can cover up a lot. It's much easier to tell color in person when you can pick through the hair than it is to tell from a photo. Let's look at the washed out photo because I think that's the easiest one.
http://www.akarenina.rii.pl/ENG/images/stories/athiara/athiara.jpg
If you look at the spot closest to the shoulder, you can see bits of tan poking through the darker coat, indicating that there is tan underneath and that the spotting is sable. It's much easier to tell on young puppies because they have a short coat, but unfortunately the picture of the same dog as a pup is too far away to see the coat very well.
Here is a link to a heavily colored sable dog, marked somewhat like Caspian without the white collar.
http://www.geocities.com/avalon_borzoi/cutter.html If you read the text after the pics, you'll see that his breeder indicates that he is sable.
Sable is a color that often looks kinda strange on borzoi, and when I first started getting interested in the breed, it often threw me for a loop.