Cylinder walls, cam to lifter wear, the gray is metallic ( iron) They must not have changed the oil too often, as that would have come out bit by bit during oil changes instead of it being allowed to accumulate
Is it magnetic? If not, it's just "sludge"; contaminated oil and soot generally from low-temperature engine operation possibly made worse by over-rich fuel mix including an incorrectly-adjusted choke; and/or misfire, and/or excess blowby, and/or coolant leakage into the crankcase, and/or faulty PCV.
