Midmo, there's a stickied thread at the top of this forum where lots of Spyderco users have posted great information about how to tell if a Spyderco is fake or not. Some forum members have even the time and energy to create very useful diagrams showing exactly what to look for in a PM2.
Please take a look and also in the future please point others toward that thread.
Short story is, your PM2 is fine, all PM2s have a flat portion of blade right before the choil.