Thanks for all the help.  I now know that the heads can not be milled (even
though the mechanic did it).   There is a  funny good luck turn to all
this, and I let the mechanic sweat a lot before I told him this.  I called
my father, who has worked at a part store back home in Michigan most of his
life. He went to visit his buddy at the local VW dealer there for some
advice.  It seems they had just done a warranty head job on a 91 Vanagon
like mine.  VW sent them two new ones, they only needed one so they GAVE
the other one to my dad to send to me.  This dealer has come through for me
in the past too.  The dealers in western New York where I live don't seem
to know beans and certainly would never be so generous.  So I had to buy
one head but found a remanufactured one.  I think I may go buy a lotto
ticket to see if my luck is still holding out.

John