Does a air flow meter have to be earthed to work 3.9 V8 Disovery 1

Hi, was wondering if anyone is formiler with a Lucas AFH55-1 air flow meter out of a V8 3.9 discovery 1. Ever since I bought the truck it’s always run rich so been looking at a replacement air flow meters on eBay and have noticed in one of the adds what looks like a wire attached to the body of the meter. In the picture of my meter there’s a screw driver pointing to where the wire is attached in the adds Iv seen.
Does anyone know if the body has to be earthed...? Any help would be much appreciated....

Mine wasn't earthed, rich running needs a lot of investigation, mine was running rich and I ended up fitting a good S/H MAFM, new lambda sensors and combined it all with a full service including plugs, leads, cap and rotor, cleaned out the flame traps and the stepper motor on the back of the plenum too, the only time ran better than that was when I fitted the new cam shaft.

Okydoky thanks for the info....