Pointshop Playermodel Issue

[HyperDrive]

Alright, so I got almost everything I want in the Pointshop set up. However there is one issue. When players buy the playermodels, if they already have one on, it doesn't unequip the old one and glitches between both or defaults to the shadow figure. Is there a way to fix this? My current code for my models:

ITEM.Name = 'Kleiner'
ITEM.Price = 250
ITEM.Model = 'models/player/kleiner.mdl'

function ITEM:OnEquip(ply, modifications)
	if not ply._OldModel then
		ply._OldModel = ply:GetModel()
	end
	
	timer.Simple(1, function() ply:SetModel(self.Model) end)
end

function ITEM:OnHolster(ply)
	if ply._OldModel then
		ply:SetModel("models/player/combine_super_soldier.mdl")
	end
end

function ITEM:PlayerSetModel(ply)
	ply:SetModel(self.Model)
end