I am working in this same area now. My early '72 pre-L had a support frame for the lower grille from the factory. The wire cloth was welded to the frame, which was then spot welded inside the valance. In my repairs, I am going to use the original grille and frame, and mount it inside the new valance with screws or pop rivets. This is simply to make any future repairs easier, as this area tends to get damaged.
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.