Check your
textured = in the gunspec.
Try using a blank if your model has its own texture info or multiple textures.
So...
textured = gun_D2.tga
...would become...
textured =
Also check the position of the weapon.
If not in the right position it will be placed out of sight.
You can check your models position by merging it with an exisisting weapon. (the HUD.X from the gamecore/guns folder not the entity bank's pickup)
Try positioning it in the same spot according to the x,y,z axis the stock weapon's model after its drawn. (not the first frames position when holstered)
You should be able to see it if it is positioned properly and textured.