The 600 series just went out of production a couple of years ago. However, they had three series, cleverly distinguished by the use of an S1, S2, or S3 suffix. I have a pair of DSM603 s3s as well as an LCR600 s3, and I freakin' love 'em. I got the demo models when my local dealer was making room for the 68X series that replaced them.
Have you been to the B&W web site? They have literature (though not pricing information) on every model speaker they ever made.
http://www.bowers-wilkins.com/display.aspx?infid=773. Use the drop-down at the left to find your speakers (note that they aren't always in a logical order, so even if you don't find them at the top of the list where you think you ought to, keep looking).
Enjoy those speakers. I'm sure they're awesome.