It's about as generic as a no-name Chinese case can get. I just went to
look, and when I looked more closely at that little pile of really cute
hardware, I saw a handful of brass standoffs, and some fiber washers.
(fibre?) So, I think, the fibre washers go on the insulated ... wait a
minute - the threads are still metal-to-metal.

The threads are metal-to-metal but the insulating washers keep the studs
from contacting more of the motherboard than they're supposed to.