The question came up in another thread this week but since the following covers more than just a couple of years thought it would better serve the membership to post some pictures here, in a new thread. Hope this serves to help others
65 trunk drop panel without back up lights
Blue arrow - hole and rubber plug
Red arrow - trunk drop/rear quarter panel drain location (same location on 66 Mustangs) Rubber torn from age and use I guess
66 trunk drop (all have back up light wire loom)
Blue arrow - hole and rubber plug
Purple arrow - back up wire, hole and grommet
67-up into at least 71 production, trunk drop example
Purple arrow - back up wire, hole and grommet
Green arrow - trunk drop/rear quarter panel drain location
Another picture showing the attachment (upper square hole) and drain holes
Its often a surprise to owners that have had rear sheet metal repair or replacement to discover the wrong panels were used leaving the car with no drains or the wrong (for the year) drains on one or both sides.