I received the K31 bayonet that I ordered from Classic. I couldn't be happier with it- the thing looks brand new. It's unserialized and unissued. I believe it's the 1918 model. The Swiss didn't mess around with these, they are works of art. I like it so much I may have to get a second one. Now to find a K31 to hang it on!
http://www.classicfirearms.com/accessories/swissbayo11-5
http://www.classicfirearms.com/accessories/swissbayo11-5