savage 99 250-3000 extra checkering

I picked up a model 99 sn 622,xxx, 250-3000 at the local gunshow. all the numbers match. It has a very pretty stock and checkering on the sides of the stock behind the receiver and also over the top of the stock behind the receiver. My blue book does not show this. Is it a special order? What is it worth? I can send pics. thanks, Scott