He is using a tangent space normalmap for the whole model, if you take a look in the WIP thread.
My thoughts:
There are a couple of spots you could probably optimize a bit further on the mesh, but nothing critical, like the front of the slide and the tip of the laser sight. Perhaps just my personal preference.
As for material definition, I think the grip looks like it should have a rubber coating(or plastic like appearance), but instead you have this “painted metal with scratches”-thing going on in there.
Aside from those two points, I like it.
Oh and by the way, which game engine is this going into?