Reverse light socket ground wire

I need to install new reverse light sockets in my 72 Demon, as they weren’t there when I bought the car. I have a random unconnected wire coming from the loom that houses the wiring harness for the tail lights that I’m assuming is the hot wire for the reverse socket but I will need to check to be sure first. However I was wondering if anyone can identify where the ground wire for the socket connects or should be tied in to. Thanks