This is a good way. For those of us who remember "stuff" like the 60's Chevys with the lamps mounted IN THE TRUNK LID, grounds were always an "interesting issue"
My 70RR, in which the sockets just "clipped" out of the housings from in the trunk, had separate ground wires attached to each socket (There were 4)
My 63, Circa 1970, "newly stationed" at NAS Miramar