Sight issue.

[-Triggerman-]

I bought a Taurus pt92 off a buddy of mine. The gun was n.i.b. never fired or altered in any way. I took it out and shot it and it hits extremely low. I have to line the top of the rear sights up with the bottom of the front sight in order to hit where I'm aiming. So much so that if I look through my rear sights at the gap under the front sight between the barrel and slide it hits just above the bullseye. Im a very experienced pistol shooter and know all about the various ways sights line up. Combat,bullseye,6:00... I even shot off a bag with various ammo just to make sure it wasn't just me. Other than being extremely low it seems to group fairly well. Is this gun covered with a warranty and if it is will I be eligible having bought it second hand? Or should I just pay 100$ for adjustable sights and hope i can raise them high enough to get me on target ? The only sights I've been able to find online for the PT92 is the crappy looking LPA sights. Does anyone know of any other brands that makes adjustable PT92 sights. This I my first Taurus and I really wanted to like this gun. But now I'm feeling like I might have just wasted my money.