I bought a C9 back around 1994. When I fired it the first time I notice that it either did not have a last round slide lock or it had one that didn't work. So my question is did they manufacture some of these without that feature? I've looked at online photos showing the mechanism on the left side of the gun that does this and mine doesn't have it. Also I have noticed the gun rattles. The rattle is from a flat piece of metal in the rear of the hand grip that is labeled 'counter balance' on the parts sheets. Is this normal?