You are correct. The side plug is machined for a magnet but does not have one. The bottom plug has the magnet. Since it is a steel plug, it is painted to minimize surface rust over time. Steel parts on the ZF were either painted black or left bare.
PANTERA INTERNATIONAL
A DE TOMASO CAR CLUB
Presents the De Tomaso Forums
The On-Line Meeting Place for De Tomaso Owners and Enthusiasts From Around the World
Clicking on the banner will take you to the sponsor's website.