color is off for my gui script?

You basically just need to divide each number by 255 or make a function that does it for you.

local last = nil

local function convert_rgb(color)
	local rgb = {}
	-- Table to return vals
	for i in string.gmatch(tostring(color), "%d+") do 
		-- Find the pattern, in this case it's the numbers before each comma. 
		rgb[#rgb+1] = i/255
		-- Store the value divided by 255
	end
	return Color3.new(unpack(rgb))
	-- return the divided rgb vals.
end

local function turnOrange(new)
    if last ~= nil then
        if new.Name ~= last.Name then
            new.TextColor3 = convert_rgb(Color3.new(227, 125, 0))
            last.TextColor3 = convert_rgb(Color3.new(0, 31, 168))
        end
    else 
		new.TextColor3 = convert_rgb(Color3.new(0, 31, 168))
    end
    last = new
end 

for i, v in pairs(script.Parent.Parent:GetChildren()) do
    if v:IsA("TextButton") and v.Name ~= "Select" then
        v.MouseButton1Click:connect(function()
            turnOrange(v) 
        end)
    end
end