Am not sure about the very early Beetles, but by the late 1960's the maker of the VW-approved Genuine Accessory towbars was Peka of Karlsruhe.
The Peka towbar sounds very similar to the Westfalia item; U-clamps around the rear torsion tubes, and further clamps around the frame horns.There was also a sort of 'T' shaped piece that bolted to the bumper itself and supported the swan-neck of the towball.
Here's a pic of what the Peka towbar looks like from a 1970 Genuine VW Accessories folder......

:wink:
'63 Karmann Ghia RHD
'72 1302LS Karmann Cabrio RHD