The Pistol Keanu Reeves is using in this...

It almost looks as if he uses two different 1911 variants, one in a black finish, and the other in maybe a brushed nickel finish. The black pistol, which he is cleaning in the opening, definitely looks like a Kimber (big surprise, given how LA SWAT only uses Kimbers, so he could easily get one from a department armorer), but the other, which he carries in most of the rest of the film, looks almost like it's got a CZ-75 style grip on it, but is most definitely not a 75. Unless it's a very heavily padded molded custom or overgrip, it's definitely the wrong grip shape for a 1911.

I think what is confusing is the fact that he is using three different stainless guns in the movie. He has both the Kimbar 1911 .45 caliber, his 2-inch stainless Smith & Wesson .38 special and a Smith & Wesson .45 or 9mm. The .38 is the gun he has on his ankle that he pulls out and accidently shoots Washington in the shoulder at the corner store shootout. The Smith & Wesson .45 or 9mm (I think its a 9mm, b/c in the first shootout at the Korean house he fires at least 10 shots before reloading, more than any .45 Smith can hold) he carries at the first shootout and throughout most of the movie. The Kimber .45 he carries to the shootout with Freemont and Coates and at Wander's house. The problem is that the Kimber and the S&W look very similar which is what creates the confusion. However, I believe always carried the .38 back-up gun and the Kimber .45 or the S&W 9mm, depending on the scene. Hope that helps.