I found the Russian cover of The Darkest Hour here: [link]
Light yellow/dirty yellow, yes? X'3 And it also shows his LEFT paw is the white paw, not his right. (even though you can't see it, his right paw is still black)
And, of course, Cats of the Clans illustrated Scourge and Bone with yellow collars as well.[link]
Yes, I do know that Cats of the Clans has SOME inaccurate art, but it does NOT, i repeat, NOT have ALL
inaccurate drawings. It is OFFICIAL art, all of them are OFFICIAL.
You may be thinking, "but Erin Hunter described Scourge with a purple collar!" that's true, but she also described Tigerstar as a she-cat once. So you can stop talking now.
I've been searching all over for that art, and i finally found it. xD i just wanted to share it with you.