The new handle may be substituted, but it will need to be shortened a bit or
it will rub on the paint.  You can just cut a bit of it off with a hacksaw.
I fill the end with epoxy just for aesthetics.  Lock is not hard to change
if you are careful.  We have used handles of both vintages in stock.
Steve Sandlin, Registered Locksmith
Steve's Lock Shoppe   http://www.steveslockshop.com
'84 Wolfsburg Westy
'79 Transporter
'00 New Beetle