O2 sensor CEL again
 

I took the Boxster in for an inspection after I once again got the same CEL for P0153 (pre-cat left sensor). I recently changed the sensor before caving in and bringing it to the dealer. when I arrive at the dealer they tell me I have to leave for several hours because the car has to cool off completely. Unfortunately I couldn't leave the car (but they still charged me 30 mins labor to read the CEL).
I called the website I ordered the Walker sensor from and they suggested swapping the front sensors to see if I would kick up a CEL on the right side, thereby showing it was a bad replacement sensor.
Anyone think of any reason why this might not be advisable?
Oxygensensors.com offered to send me a replacement Walker sensor but I'm going to try the swap first before I go back to the dealer.