PHP Code:
entity_set_string(id, EV_SZ_viewmodel, "models/v_model.mdl")//self view model;
entity_set_string(id, EV_SZ_weaponmodel, "models/p_model.mdl")//player's model, 3th personal eyeshot;
entity_set_model(EntityID, "models/w_model.mdl")//weapon(weaponbox)'s world model, droped or on ground;
if you want change current weapon model to specifically "model", use "CurWeapon" event, about some "events":
http://wiki.tcwonline.org/index.php/..._1_Game_Events