I just did a cold check on the 81. Yes, I need to change the oil, and I also see it's a half-quart low. But it covers the entire area, not just a remnant. The photos you posted it looks like remnant of oil. This cold check is popping the hood and checking the oil level without any engine rotations, and not wiping the dipstick, it shows how everything settled in and at what level since I drove it last week.
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