We talked about this a while ago. The link is below to the thread. I had put lots of pictures up then that still work.
In short, After SKB's relationship with Ithaca ended Mitsui of Chicago, Ill. picked a contract to import SKB's. One of the models offered was a fully engraved boxlock with fixed chokes called the 400. This relationship lasted less than 3 years. I have never actually seen a 400 sidelock like the ones mentioned in the blue book of gun values.
http://www.doublegunshop.com/forums/ubbt...1510#Post161510