I don't know enough about this, but isn't the article saying that the appearance is deceptive:
The chips on Elemental servers were designed to be as inconspicuous as possible, according to one person who saw a detailed report prepared for Amazon by its third-party security contractor, as well as a second person who saw digital photos and X-ray images of the chips incorporated into a later report prepared by Amazon’s security team. Gray or off-white in color, they looked more like signal conditioning couplers, another common motherboard component, than microchips, and so they were unlikely to be detectable without specialized equipment.
If the photo in the article is real you wouldnt be able to identify this component as compromised "just" by visual (even xray augmented) inspection. TVS Diode Array looks the same from the outside, whats more its build in same way with silicon die embedded in tis structure. Other than signal analysis it would take decapping every single component of a motherboard to find this implant.
The chips on Elemental servers were designed to be as inconspicuous as possible, according to one person who saw a detailed report prepared for Amazon by its third-party security contractor, as well as a second person who saw digital photos and X-ray images of the chips incorporated into a later report prepared by Amazon’s security team. Gray or off-white in color, they looked more like signal conditioning couplers, another common motherboard component, than microchips, and so they were unlikely to be detectable without specialized equipment.