Hinrik, the early-war bikes had the pre-war style aluminium mounts. There then followed a squarer looking cast 'mazac' version and then the cast iron 'spectacle' type.
Life is complicated as both the 1938 civilian engine and the 1948-on civilian motors used aluminium platforms that look similar to the WD type but have different dimensions.
As far as I know the cast iron platform was made for the WD16H, however, the mounting holes on the one on ebay don't look in the right place. The one on the website does look right.