I don't know where you changed  your settings and what you saw after stopping the
recorder. Did you see something like:
sub macro1()

end sub

or nothing at all? There are certain commands which the macro  recorder does not
record at all. When you change the toolbars for example, this process  is not
recorded. All you get in this case is an empty macro as shown above.

No, I did see sub macro1().

The problem is, the code  won't reflect the changes I made with
printer properties.

Looks like VBA can't directly control printer. I don't know how to
play with printer server to get the settings changes so that duplex
printing can be default setting.

You got what I'm saying now?

The usual work around is to make a second printer definition where the
default attribute is double sided. This is down outside of Excel. Go to the
Control panel, select printers and add a new printer. You can have multiple
printer definitions pointing to the same printer. Of course, choose an
appropriate name for the printer "Laserjet 1012 DoubleSided".

Within Excel, change the printer attributes by selecting a different
printer.

"down outside Excel" should be "done outside Excel"

It saves me from reading a mountain of printer
manual books.