Maybe one of them is this:
http://www.sigarms.com/products/sigpro-models.asp?product_id=195
The "-9" seems to indicate the special.
The slide is stainless, and blackened like the regular model, but it looks like a "brush flats" has been done to it, to remove the blackening, on the higher flats. It looks pretty cool.
I wonder what the contrast sights look like?
There are some differences between the blue line, and the other model, unless there were year/model changes between the time I bought mine, and my friend Josh bought his.
I have a slide stop that extends slightly, it's fairly easy to field strip.
Don't get me wrong, it doesn't fall apart or anything.
Now Josh's 2340 has a slide stop that doesn't have a protrusion that you can push out with your fingers.
It has a little dimple "belly button" for lack of a better term that you have to depress with a pen or similar blunt instrument to field strip it.
It's not easy at all, even with a pen. Not even after thousands of rounds. In a bright room with clean hands and a clean floor.
It would annoy me to the point of insanity, thankfully it's not my gun.
Btw, his has the blue line crest, and mine doesn't.