Quoted from EM-PINMAN:
Could use a 70's Gottlieb Coin Door bracket which is located on the inside of the door. May have been used on 60's models as well single or Multiplayer, so fairly common. I believe it keeps the Lock Down Bar Latch Handle secure when the Coin Door is closed. One of my machines was missing this when I bought it.
Update: 3/6/2015 - Got one coming from a Pinsider, Thanks Again John_in_NC.
Gottlieb coin door bracket 003.JPG (Click image to enlarge)
I wondered the function of that bracket Ken-thks for clarifying.