'65 Barracuda Body Plugs under Rear "Mat"?

[dibbons]

We have four holes under an insulating mat, one of which is the exit for the fuel sender wire. Two of them dump into the frame rails on either side and still another one on the driver's side just empties into thin air beneath the vehicle.

I have a photo of the mat, but not beneath the mat after it was removed. Anyone have an image of how the plugs, if any, are set up under there? Anyone know if any of the three additional holes serve any purpose? Thank you.

 

[moparmat2000]

The 2 lined up w framerails are leftovers from assembly line jig which likely had pins sized to the holes to line the floor pan up with the framerails. Black plastic Caplugs snap in the holes.