BTW, it is now a discontinued model but you may still able to get it~~

I would recommand a clip point, non-serrated, auto version

all those knifes are very similar, but the closest one if found so far is this one:
[link name=][/link]http://www.blackhawk.com/product/MOD-CQD-Mark-I,144,37.htm

Sam's knife is a modified Benchmade 140SBK Nimravus.

Its a double-edged combat knife. Overall length 7 1/2 inches with a 3 and 3/8 inch, black oxidized high carbon stainless steel blade to prevent reflections and a black polymer rubber handle.

http://www.knifecountryusa.com/store/product/106447.106475/master-of-defense-knives-253-a-2-steel-besh-xsf-1-fixed-blade-knife.html

IS it like this one? I think it looked like this in Chaos Theory. Could be wrong havent played in years.

Chaos Theory is a Gerber Guardian
DA is a Benchmade
Several of the pic posts numbskulls have made are flat out wrong.