If your rear sight has NOVAK on it, it's most likely a genuine part. If not, it's probably an "unauthorized" copy of a NOVAK. IMO, BIG DEAL! If the sights were installed with equal distances in the dovetail from left and from the right, and the front fiber optic is centered the same, that gun should be zeroed. If not, it's easy to drift the rear one way or the other for POA to POI. What sights are you wanting to change to? .....Also, I ordered a Stingray yesterday and it should be in my hands Monday.....my 3rd Tisas and might not be the last.......well, not 3 but 4. I also have the Tisas (MAC 2) Tactical shotgun which really does have interchangeable parts with a Benelli M2 down to the screws, gas system, et al. Turkey's getting a few of my greenbacks lately.