A Puzzle

The following images are part of a puzzle I'm trying to figure out. I'd appreciate any input anyone can offer.

These parts are for a 1976 Mercedes 300D. A friend performed a compression check on the engine for me. I'm grateful to him for giving me a quantitative evaluation of the compression in my engine, but unfortunately he uncovered a puzzle. It is such a puzzle that neither he nor I are comfortable putting this vehicle back on the road.

You see, after removing the injectors from each of the five cylinders, he also pulled out what he thought were heat shields (from underneath each injector). These are the top-hat shaped thingies.

Oddly, the new heat shields for my injectors look nothing like the parts my friend removed. (See the bright yellow-metal colored washer-shaped thingies.)

These washer-shaped thingies are what we've both seen, and installed successfully, as replacement injector heat shields.

Whatta puzzle!

Please contact me directly with any guesses, explanations, or other information that might be of help in getting my Benz back on the road!