Beats Tour 2.0 serial?

Hi, I copped a pair of Beats Tour 2.0 from a guy on eBay with lots of good feedback and 100's of sales so assumed it would be all good. However, I wanted to make sure. Found here http://www.beatsbydre.com/support/find-serial-number.html that the serial should be on the cable of the right earbud, but, it also says above this "Note that some products might not have a serial number." my beats don't have a serial on the cable. Also, on the headphone jack are the characters "K4713". I tried to google this to see if anything comes up but I found nothing. However when typing it out it was a suggested search by google in the drop down box.

Can anyone with these headphones confirm for me if the serial should be there? I think they're fake, but when I used the "RedLaser" barcode scanning app on my iPhone on the barcode on the box it did come up as Beats by Dre Tour 2.0.

Thanks if anyone can help.