Am I wrong? Let me check -
I do have 5.7.3.1 -
Edit: The serial number is (deleted)
but I can't find whether that means it's a P3.
I got it for Christmas last year so maybe it is. I already had the first PW so maybe I just assumed this was the second. Even better, if so!
Redacted the serial number. Please don't give that away to people who might use it for evil. 
We only need the first 4 or 6 digits.-- eschwartz