After some years, I was able to do something better.
Anyway, here you the new features:
*models re-exported again (because the ones I exported at the time they looked like horrible);
*bones (all made by me);
*HD textures (obviously);
*sizes according to L4D2 characters;
*"rotating" animations (for all the weapons) and firing animations (for the MG, the RL, the GL and the LG) made my myself;
*festive lights (for special occasions) made by Sly7745;
*additional skins for the Lasergun made by cyann3 and tuneful;
*simple physic.

Updated rendering.

Added "rotating" animations made by me (slow, normal and fast ones) to all the weapons (except the knife);
Added firing animations to the minigun and the laser gun.
Fixed colt bone.
Added bone for the scope of the sniper rifle.

Fixed sizes of the most part of the weapons.
Fixed smoothing about some weapons like the Cannon.
Added missing normal maps to some weapons.
Fixed some "bugs" about textures.
Other minor bugs have been fixed.

Improved textures.
Cloaking skill added.