When my group 4 was built, they welded in metal in the car weak spots (one being the tail light area). You could probably have it done and then just repaint that section of your rear end.
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.