[T3] Type 3 oil cooler tin piece

[Phil Ostronic]

There is a small tin piece that goes on the block before the oil cooler and its bolts are fitted.  On a Bug this has been nicknamed the "Hoover Bit."  The shape is different but the idea is the same, to seal the cooler better.
 
I never have found one on my two T3s I've owned, including the '71 I am now rebuilding.  I actually assumed they didn't use it, and that  the Bentley and/or Elfrink photo I saw was from reused from a Bug manual (which they both often did).
 
However, after seeing an ad for the part on the Samba, specifically for a T3, I figured I was wrong.  I am buying the part, and my builder is on hold waiting for it.
 
However, I've read that very early Type 3 motors used a Type 1 steel cooler with an adapter.  Maybe this tin piece was only used for those?
 
Do you know the part, and do you know its correct application?
 
Thanks,
-Phil
=========================