I have seen a few shots in Mobygames, Gamespot and so on, all of them have blank green sight on PC in every weapon with screen as sight. I guess the original crappy port was just like this. But it is maybe a Direct3D fault. The game was D3D 7 or 8, i'm not sure.

This is how the original Playstation 2 version looked like.

https://youtu.be/xIgIjFev260?t=840

The PC version have a few other quite minnor errors and, again, i'm not sure if this is how the game looked like or it is a rendering error.

This Gamespot screenshots of PC already featured these errors back in the day.

And Playstation 2 version shots looked properly. It is the console version, you can see it in the 16bit framebuffer artifacts in the, supposed to be, shadows.