Nobody seems to have answered the question of how can you tell the difference.
If you look at the dump valve there is a little pipe on the top which is just vacuum. there is usually to other ports on them, one on the bottom and one on the side. one of them will be into the pipe coming from your air filter (TIP), if the other is open or has a cone on it then it is venting to atmosphere, if there is a pipe on it then it is recirculating, if it actually has 3 ports one in the TIP, one with a cone and one with a pipe then you probably have a split valve whereby it recircs half and vents half.
the other option is to post a pic of it lol
if its atmospheric it will have vacume (little pipe to the top) and be mounted on the pressure side of the turbo (left side of the engine as you loot at it) it wont necessaraly have a cone etc, just a hole in the main body with a piston behind.
a recirc valve has a pipe shoved on one end and the other is mounted in the tip. there will also be a little vac pipe to the top of it from the 249 valve.
i'm running stage 2 software now and i've tried 5 different valves (standard, forge 007, bailey atmospheric, turbo dynamics vee port atmospheric and something the guys at revo hooked me up with) the forge 007 was the quietest opperating by far for my application but you will prob find the induction kit choice you have will make more of a difference to the dv noise than anything else.
i'm running a recirc now but its far louder than any valve i've valve i've used so far, but then thats possibly due to the ally pipe from the mass air to the filter in the bumper.
But i like to hear a flutter from under the bonnet
you'll find something to your taste out ther i'm sure but the 007 is a good option and should hold all the boost your running on a ko3
anyways, i've chuntered on long enough now! good luck with the project chap!