Do 1969- 1970 license plate lights have ground wire

[fairlane292]

Do 1969- 1970 license plate lights have ground wire. It appears that the 510 example had a two wire socket (one being ground I believe). I'm looking to buy a couple 1969- 1970 license plate lights and the few I've seen so far just have a single green wire (from the socket). Side lights (front at least) have a single green socket wire but also have a black ground wire to the light body. Any ground wire to the light body of the license plate lights? Thanks guys!!

[redroadster]

My 70 just has the pos wire to the plate lamps
It gets power thru body ground

[Loy]

Yup I believe the contact point ground is the mounting bolts in the trunk.