Help, Xbox 360E Processor

On the motherboard, the processor, mine does not have the square cap/cover on top. I bought my 360E new in 2014, so you would think it would have it. Where can I get the square cover? When I applied new thermal paste, there was no cover, but there is a small gap under the heat sink. I had to really bend the x clamp to give it the leverage so the heat sink would not wiggle as much as it was, just wiggles a tad now but still the gap. When I removed the heat sink there was old thermal paste on the heat sink as well, so the cover was never put on. I would like to buy the cover for it, where can I find one?