How do I check if player has certain UserId?

I cannot seem to make the script check if the player's UserId is correct.

Here is my code:

local Players = game:GetService('Players')
local Player = Players.LocalPlayer

if script.Parent.PrimaryPart then
	if Player.UserId == 171275787 then
		for i, v in pairs(script.Parent:GetDescendants()) do
			if v:IsA("BasePart") then
				if v ~= script.Parent.PrimaryPart then
					local wc = Instance.new("WeldConstraint",script.Parent.PrimaryPart)
					wc.Name = "weld"
					wc.Part0 = script.Parent.PrimaryPart
					wc.Part1 = v
					v.Anchored = false
					v.CanCollide = false
					v.Massless = true
				end
			end
		end

		script.putBehind.Disabled = false
	end

end

Please help, Thanks