If the body were aluminum I don’t think anyone could tighten a head shell bolt that tight to break those mounting tabs as they are quite thick.
I have some reviews and tests in the magazines of the time and they claimed that this "sintered aluminum" hard as ceramic but it does not have a ceramic body because otherwise it would have cost a lot more..
If you want I can also show you the owner's manual where it is written what the body is made of ... I am a reliable person and I do not like to write saloon talk.