Dennis, I have no measurements for you, but I did note that there seems to be a large disparity in the rear body panel; I found at least three different license plate recess dimensions- none of which were Euro cars, incidently- and on one undamaged 1971 pre-L, the plate recess was offset towards the left side by 4". Even to an untrained eye, it looked off-kilter, and since the car was stripped to bare metal, one could see the panel had been made that way. There are also several different split bumpers, at least two of which are made to different widths and lengths.
Bottom line: don't worry about it; bumper placement should be where you as the owner like it.
PANTERA INTERNATIONAL
A DE TOMASO CAR CLUB
Presents the De Tomaso Forums
The On-Line Meeting Place for De Tomaso Owners and Enthusiasts From Around the World
Clicking on the banner will take you to the sponsor's website.