Well he only has 9 feedbacks, and while all are good, I'd still be a bit hesitant, but on the other hand, it is a pretty good deal...but shipping will most likely be a PITA. Aren't there brand new aluminum DSs on 3si for $475? Have you checked those?
Edit: here is the thread I was talking about
:
http://www.3si.org/forum/showthread.php?t=235092
Edit #2: Nevermind, apparently his had fitment problems and they are getting returned and it isn't looking so good anymore. So that ebay deal is looking better and better.