They were included in all new kits from AMI, as far as I can tell. Even the very last batch that Fujita sold in spring 2009. I bought multiple new kits from different vendors (Tops, Fujita, Excellent) from 2007-2009, and every single kit had both the CD and piggy mascot inside the box. Not all of the brand new kits came with the poster or promo flier, however, which is why I consider those optional.
With that said, you can consider them optional if you like. They're nothing special really.