The two types are both plastic. The newer type 2 is some type of glass packed nylon. The older type 1 is solid plastic. I have not found anyone that makes a aftermarket metal one.
If your motor is a 2000/2001 and has never been opened for rebuild then you have the older type one. And even if it has been open and the gear looked good it may have never been replaced.
The Merc shop I have taken my motor to told me about the 2 types and that I had the first one. He made it VERY clear both types are ticking time bombs and I'm lucky it has not giving out yet. I found a quite few posts about these gears on different forum sites after he told me about them. I think there was a thread here as well that kinda talked about them.