Well, the weapon is a base 1911 model. It's called a Matchmaster and is believed to be constructed by Safari Arms. It appears to have an extended 10 round magazine. The "thing sticking out of the front of the gun with holes in it" is called a muzzle break, and the one on the weapon isn't that impressive from a construction standpoint, but reports have it made of titanium, which would be completely ridiculous from a cost versus effect stand point, but whatever floats your boat.
There is on line speculation that the weapon is 10mm, and not .45 ACP, as would be the norm.
The custom engraving is done to match the tattoos on Jolie's character's body. If you look at the hold of the weapon in Jolie's left hand, you will see that the tattoo's match up with the engraving on the pistol. Never mind the fact that there is no LH safety on the weapon in question.
All in all, I appreciate the fact that they gave my girl a 1911, but I would have chosen a much better model for her.