I would imagine that they are a plastic reinforced w/fiberglass.
The issue w/plastics are w/the heat of the engine.
Over time they tend to fatigue and crack.
I would also imagine, w/the tightening of the drain plug, you will need to be especially careful. I would recommend using a torque wrench when tightening, looking up what the torque value is for the drain plug.
Well mines built 5/22. I went out and checked my oil and it is mid-range ice cold. Also, I did not notice the pan being a composite during the oil change. So, I think I'm a 5.3. But I'm going to mark my engine so in the future some oil changer does not fill it 6.6. and not understand why dipstick is so high.