The "revolver for under $600" thread from last week specified EITHER .357 mag OR .38 special.
http://thefiringline.com/forums/showpost.php?p=5809666&postcount=1
Limiting to .357 is going to push that $600 envelope, but it is still doable. In S&W, and blued, as you specified, your choices are going to be pretty well limited to Models 19 and 28. The Model 27 is going to be very, very hard to find for anything close to the $600 figure. I have a finish challenged, but very sound Model 19-3 I gave $325 otd for about three years back. Maybe four. You would probably pay $450-$550 for that gun now. It would be a bargain at $450, and a fair deal at $550. You start getting in the 95%-plus guns, and price climbs accordingly. That happens to be the only .357 revolver I own. I am just not that big a fan of .357 in a handgun. I love it in lever action carbines.
You drop back to .38 special, which is tied with .45 Colt for my all time favorite, and you can come in well under that $600 wire, even for an adjustable sighted gun, which means Model 15. You can buy a pretty dang good Model 15, which is my all-time favorite revolver, for $500. You can shop around and get one with finish wear for $350-$450. If you forego the adjustable sights, and go with a model 10, you can get serviced easily for the $350. I love my Model 10s.
It will take some effort. I scan a couple of different Swap and Sell forums every day, especially one that is limited to Georgia. At any given time, there are half a dozen S&W revolvers listed. The more years you wait, the more they are going to cost. They'll be out there, because there are just so many of them (especially Model 10s), but they will be more and more expensive each year. Ten years ago, I was paying $150-$175 for a good pinned barrel Model 10. Five years ago, it was $250. Today, it is $300-$350.