After some info on the difference between a 16V head gasket and a 20V head gasket? I still don't understand why run a 16V gasket on a RWD 20V?

I have pictures of the two heads, and the gasket which came off my engine. I don't know what type came off it, and with the gasket on both heads does the same thing, and only blocks 1 hole in the head (as pictured).
Any advice or comments welcome.



This is the hole that will be blocked on the 16V head.



And the same hole on my 20V head.