Jaspers will have "12.1A" as the power configuration written to the left of the serial number, the power plug that connects to the back of the 360 will be plastic coated instead of the previous models metal coating. The power brick will also have ventilation slots across the top where as the older brick only had ventilation at the ends.
The older bundle was still advertised in the store I went to so providing your local jb has stock you should be cool. It will be up to you to make sure you get a jasper. Ask to look in the box, my local store manager had no issues with this, if your lucky you can move the 360 around in the box slightly (without opening the box) so the serial number is more visible through the "peep holes".
Set up my jasper yesterday big improvement over my 06 model that never gave me any issues so I feel a little guilty retiring it, still it will find a new home soon enough.
Thanks for the heads up.