Not really sure what you mean the hub is held on to the spindle by the big castellated nut, do you mean the drive shaft to the spindle?
try this site to get the part number then try a VW main dealer
http://www.vagcat.com/epc/" onclick="window.open(this.href);return false; you need to register but its free and a good source of what parts are still available from VW.
This page shows the 1971 rear axle assy http://www.vagcat.com/epc/cat/vw/T2/1971/29/53/362929/" onclick="window.open(this.href);return false; all the fixing seem to still be available from VW