Axis SS Ground wire question

I made my own covers for the back of my Axis SS. I made them out of wood so now I am wondering about the ground wire that usually goes under the stock metal cover. Would it be in my best interest to put some sort of metal, such a maybe aluminum foil, underneath my electronics cover? I can get a thin sheet of something and glue it to the bottom of the wood cover so that the wire can at least touch something metal.

I actually have been playing with different wood covers that I made and have no problems whatsoever but I just made some new ones, got to thinking about that wire, did some checking and now am questioning if I should do something metal underneath.

Necessary or No?

Thanks!