Thanks Bill R.,
It does look like all the VDO temperatures sensors are electrically identical, and all I have to do is be sure the threads match the thermostat housing.
Interestingly, the 1/2"MPT style in that EBay listing you posted is on the VDO website as obsolete and no longer manufactured. If mine turns out to have a 1/2" thread, I think I'll buy two...
Annapolis, MD, USA