How would I make it so that the code cannot be used again if you leave then rejoin?

I don't want players to be able to enter the code again if they leave then rejoin. Would I need to use datastores?

local codes = script.Parent.Parent.Codes -- location of the codes

script.Parent.MouseButton1Down:Connect(function()
	if script.Parent.Parent.codeBox.Text == "Alpha" then
		if codes.Alpha.Value == true then
			script.Parent.Parent.codeBox.Text = "Already Redeemed!"
		end
		if codes.Alpha.Value == false then
			codes.Alpha.Value = true
			game.Players.LocalPlayer.leaderstats.Credits.Value = game.Players.LocalPlayer.leaderstats.Credits.Value + codes.Alpha.Reward.Value -- change Credits to your currency's name and the number to how much you want to award them for entering the code.
			script.Parent.Parent.codeBox.Text = "Redeemed!"
		end
	end
end)

Also my game is Filtering Enabled.