I think the marks on the inside of the pan are from normal contact between the plastic pickup and the pan. I'd say by designed there is no room between them. It appears the four footed beast is supposed to keep large droppings away from the screen.

My doctor's diesel threw a turbo blade which found its way into the pan and beat a hole through the screen. I'd say the plastic parts in your pan resided against that screen when the engine was running and did its best aided by oil pressure to break through. However, I wouldn't believe the restrictions they produced did any damage to the pumps volume or pressure producing ability.

What pressure did your gauge show during idle and while driving?

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84 300SD
85 380SE
83 528e
95 318ic