I think there were several limited runs. I bought one 37-2 DAO in 2005 NIB for $325. Its my everyday BUG on and off-duty. Its marked .38 S&W Spl. on the right side of the barrel (no +P designation) and Smith & Wesson on the left side, has the laser etched "Airweight" and S&W logo on the right side of the gun (sideplate), the pre-magnum frame, and the serial number on the butt and above the 37-2 on the inside of the frame. It has the bobbed forged hammer w/ firing pin and the forged trigger, and of course, no internal lock. It has a matte black finish and a DAA serial number prefix.
I bought two more NIB in 2008 and paid about $475 for each of them (I suspect I overpaid a bit, but I love my 37-2 DAO above, and I wanted some spares before they completely disappear). They too have bobbed forged hammers with the firing pin mounted where it should be, forged triggers, pre-magnum frames, and no internal locks. However, the S&W logo is on the left side of the frame under the cylinder latch, and they are not marked "Airweight" on the ride side or anywhere else. They are marked .38 S&W Spl. +P on the left side of the barrel and Smith & Wesson on the right. The serial numbers are located in the same two places listed above (butt and above 37-2), but they are also laser etched on the left side of the frame under the cylinder. They both have the matte black finish and both have DAC serial number prefixes.
I am very happy with my 2005 version. The two 2008 versions seem to be of equal quality, fit and finish, etc. I haven't fired either of them though, so I can't comment there.
$529 is a little high, but given current no-lock prices, its not as high as it would have been in 2005.