There are source files for two Half-Life weapons here, the Gluon Gun and the Assault Rifle.  There are three versions of each model: the weapon as seen if lying on the ground in the world (the world model); the weapon as seen held by an opposing player (the DMplayer model); and the weapon as seen when armed by the player himself/herself (the view model).  All three versions must be created for a complete Half-Life weapon.