Really?, I must say i'm suprised. The son's of russ were the only succesor chapter to the space wolve's. They are very rare now as they are discontinued.
Could you please post some pics, I want to see them for myself. It's just that I've heard they had a large amount of wulfen units. Mainly because I inherited a large army and it's over twenty years old, I can't wait to see how old yours are!