I'm assuming you mean this? http://www.ebay.co.uk/itm/MICROSOFT...780?pt=LH_DefaultDomain_3&hash=item3cf8d89ee4
Whilst a lot of the warnings/caveats do seem suspicious, the final photos look like maybe these were bulk sales for educational or institutional use?
I brought from this seller and the pen looks genuine to me. Works 100% no issues. I did do a search online about fake Surface 3 pens and didn't find any reports of any, so I thought this would be a safe get try this. Got tracking number and everything, took only a week posting to the UK.