Weapons with custom models are invisible

[AssMuffin]

All of my TTT custom weapons are invisible in both first person view and when dropped on the ground. The clients are downloading the models, but it doesn't show up in game. Anyone have any idea what's going on?
Here's the code for my weapon:

if SERVER then
   AddCSLuaFile( "shared.lua" )
end

SWEP.HoldType			= "shotgun"

if CLIENT then
   SWEP.PrintName = "Spas 12"

   SWEP.Slot = 2
   SWEP.Icon = "VGUI/ttt/icon_shotgun"
end


SWEP.Base				= "weapon_tttbase"
SWEP.Spawnable = true
SWEP.AdminSpawnable = true
SWEP.ViewModelFlip = false

SWEP.Kind = WEAPON_HEAVY
SWEP.WeaponID = AMMO_SHOTGUN

SWEP.Primary.Ammo = "Buckshot"
SWEP.Primary.Damage = 12
SWEP.Primary.Cone = 0.085
SWEP.Primary.Delay = 0.8
SWEP.Primary.ClipSize = 8
SWEP.Primary.ClipMax = 36
SWEP.Primary.DefaultClip = 900
SWEP.Primary.Automatic = true
SWEP.Primary.NumShots = 8
SWEP.AutoSpawnable      = false
SWEP.AmmoEnt = "item_box_buckshot_ttt"
SWEP.ViewModel			= "models/weapons/v_shotty_spas-12.mdl"
SWEP.WorldModel			= "models/weapons/w_shotty_spas-12.mdl"
SWEP.Primary.Sound			= Sound( "weapons/spas12/spas_shoot_pump.wav" )
SWEP.Primary.Recoil			= 7
--SWEP.IronSightsPos 		= Vector( 5.7, -3, 3 )
resource.AddFile("models/weapons/v_shotty_spas-12.mdl")
resource.AddFile("models/weapons/w_shotty_spas-12.mdl")
resource.AddFile("sound/weapons/spas12/spas_shoot_pump.wav")

SWEP.InLoadoutFor = {}

SWEP.IronSightsPos = Vector( 5.14, -5, 2.14 )
SWEP.IronSightsAng = Vector(0, 0.8, 0)
SWEP.SightsPos = Vector(5.738, -2.951, 3.378)
SWEP.SightsAng = Vector(0.15, 0, 0)
SWEP.RunSightsPos = Vector(0.328, -6.394, 1.475)
SWEP.RunSightsAng = Vector(-4.591, -48.197, -1.721)

SWEP.reloadtimer = 0

function SWEP:SetupDataTables()
   self:DTVar("Bool", 0, "reloading")

   return self.BaseClass.SetupDataTables(self)
end

function SWEP:Reload()
   self:SetIronsights( false )
   
   --if self.Weapon:GetNetworkedBool( "reloading", false ) then return end
   if self.dt.reloading then return end

   if not IsFirstTimePredicted() then return end
   
   if self.Weapon:Clip1() < self.Primary.ClipSize and self.Owner:GetAmmoCount( self.Primary.Ammo ) > 0 then
      
      if self:StartReload() then
         return
      end
   end

end

function SWEP:StartReload()
   --if self.Weapon:GetNWBool( "reloading", false ) then
   if self.dt.reloading then
      return false
   end

   if not IsFirstTimePredicted() then return false end

   self.Weapon:SetNextPrimaryFire( CurTime() + self.Primary.Delay )
   
   local ply = self.Owner
   
   if not ply or ply:GetAmmoCount(self.Primary.Ammo) <= 0 then 
      return false
   end

   local wep = self.Weapon
   
   if wep:Clip1() >= self.Primary.ClipSize then 
      return false 
   end

   wep:SendWeaponAnim(ACT_SHOTGUN_RELOAD_START)

   self.reloadtimer =  CurTime() + wep:SequenceDuration()

   --wep:SetNWBool("reloading", true)
   self.dt.reloading = true

   return true
end

function SWEP:PerformReload()
   local ply = self.Owner
   
   -- prevent normal shooting in between reloads
   self.Weapon:SetNextPrimaryFire( CurTime() + self.Primary.Delay )

   if not ply or ply:GetAmmoCount(self.Primary.Ammo) <= 0 then return end

   local wep = self.Weapon

   if wep:Clip1() >= self.Primary.ClipSize then return end

   self.Owner:RemoveAmmo( 1, self.Primary.Ammo, false )
   self.Weapon:SetClip1( self.Weapon:Clip1() + 1 )

   wep:SendWeaponAnim(ACT_VM_RELOAD)

   self.reloadtimer = CurTime() + wep:SequenceDuration()
end

function SWEP:FinishReload()
   self.dt.reloading = false
   self.Weapon:SendWeaponAnim(ACT_SHOTGUN_RELOAD_FINISH)
   
   self.reloadtimer = CurTime() + self.Weapon:SequenceDuration()
end

function SWEP:CanPrimaryAttack()
   if self.Weapon:Clip1() <= 0 then
      self:EmitSound( "Weapon_Shotgun.Empty" )
      self:SetNextPrimaryFire( CurTime() + self.Primary.Delay )
      return false
   end
   return true
end

function SWEP:Think()
   if self.dt.reloading and IsFirstTimePredicted() then
      if self.Owner:KeyDown(IN_ATTACK) then
         self:FinishReload()
         return
      end
      
      if self.reloadtimer <= CurTime() then

         if self.Owner:GetAmmoCount(self.Primary.Ammo) <= 0 then
            self:FinishReload()
         elseif self.Weapon:Clip1() < self.Primary.ClipSize then
            self:PerformReload()
         else
            self:FinishReload()
         end
         return            
      end
   end
end

function SWEP:Deploy()
   self.dt.reloading = false
   self.reloadtimer = 0
   return self.BaseClass.Deploy(self)
end

-- The shotgun's headshot damage multiplier is based on distance. The closer it
-- is, the more damage it does. This reinforces the shotgun's role as short
-- range weapon by reducing effectiveness at mid-range, where one could score
-- lucky headshots relatively easily due to the spread.
function SWEP:GetHeadshotMultiplier(victim, dmginfo)
   local att = dmginfo:GetAttacker()
   if not IsValid(att) then return 3 end

   local dist = victim:GetPos():Distance(att:GetPos())
   local d = math.max(0, dist - 140)
   
   -- decay from 3.1 to 1 slowly as distance increases
   return 1 + math.max(0, (2.1 - 0.002 * (d ^ 1.25)))
end

[AssMuffin]

I've been having this problem for a while now, does anyone know anything?

[bmazoka]

Is it possible that they are not downloading the materials for that weapon?