I can't say for certain until you try them, but it's much more likely than unlikely that they will work with your laptop, purchased 5 months ago. The problem is that the sound quality will be not as good as it could be if Apple supported A2DP. They still do not as of 10.4.5, as was mentioned in an earlier post.
As Apple is the know leader in the universe right now for all things audio, it is my assumption that Apple WILL support it in the future, in fact they MUST. When it will happen I believe is the question.
To summarize, you do not need, nor do you want the AirCable dongle, as your 5 month old PB has bluetooth built in. The headphones should work fine, but reduced sound quality, for now.
I'm using the Plantronics 590A's which support A2DP and sound great with the phone-plug adapter, but when I use a USB dongle the quality diminshes. For the heck of it I tried an A2DP compliant dongle, and it turns out Apple doesn't support headphones with the dongle - go figure.
It's a waiting game. Hopefully Apple will see these posts and realize that they are not the leaders in this tech, Microsoft is, and they better catch up with it, FAST!
Take care!
PB Ti G4 Mac OS X (10.4.4)