Good Grief , 
I have observed that cast aluminum oil pans are usually designed to increase the strength of the lower end of the block. I prefer cast aluminum pans regardless though. They seem less likely to leak from any sealing surface.
Not having had one, do aluminum oil pans have aluminum threads for the oil plug? Or a steel insert? Aluminum threads would seem likely to strip.
I donāt think thereās an insert, at least on most aluminum oil pans. Lots of threads and not a lot of torque when tightening keeps them from stripping, I guess. Although it does happen of course.