I am looking at an early P89 with a serial prefix of 300. It has single-sided decocker. IT is in "ok" shape. I noticed that the slide has a screw type thing on top in front of the rear sight unlike the later model being on top of the rear sight. The slide also has a pin going through it on the side near the rear that I don't see on my newer P89. Were there any problems with these early P89's ?