Please help

[goldcoast14k]

I need a knowledgeable person to help verify the authenticity of my recent ebay purchase. I thought the listing was from a reputable private seller and I paid what seemed fair market value for a Native 5 CPM REX 45 Sprint, C41PBORE5. Here is the listing
https://www.ebay.com/itm/293620744735

The knife appears to be legit but I noticed the action of the lockback is terribly gritty. I acknowledge that lock-backs are not the quick free falling action of PM 2 compression locks however, out of the box my delica was butter smooth by comparison (just heavy resistance from the spring bar). I also notice the end of the tang is different; a polished / beveled radius is present around the end of the tang from the notch cut out where the blade lock up occurs.

Here are pictures of what I received in the box.
https://photos.app.goo.gl/u1VzizgDAcMhYqPd7

[Accutron]

Your knife is authentic. Everything looks correct, and sprints aren't really counterfeited.