The duct work for the fresh air ventilation is non-Westy only.  The one on
the left would stop where the back of the seat behind the drivers seat is and
the one on the right would end where the sink/cooler is.  I bought a 1973
window van for the engine and other parts for my 1972 Westy and that is how
it was set up.

P.S.  If anyone is interested, this '73 is now at the "Beetle Barn" in
Cambridge, Ohio.  It is a parts lot that has only Volkswagens, air and water
cooled.