Yes, the video is in Spanish, but it's fairly easy to follow even if you don't know that language.
I can't really help you with the gun rigging as I'm only a car modder and a texture artist, but I don't think you would need to animate the models. I believe you may only need to setup a few nodes or something (again, I can't confirm this because I don't model weapons for IV).
I would ask for support/advice from someone who does work on IV weapons.
Good luck!
thanks murphy
ok. anyone that can answer my last question about whether or not i need to animate the model for it to work in gta iv please comment or pm me.