Your shield is certainly a very unique and very cool piece. It looks like you have the entire front flange w/3 holes missing, 2 holes missing or plugged in the center, and the 2 holes you do have at the back end need to be beefed up a bit. The 2 holes at the outer edge flanges look fine.
There are several products listed for plastic repair such as; Mxbon 105 (professional cyanoacrylate adhesive), 3m--Dura Mix (autobody supply.net), & Plastic Weld (Napa)...however, I like the advise given for fiberglass mat & resin.
As difficult as this part is to find I would highly recommend drilling reputable body shops before you decide what course of action to take. To make matters worse, the shields original configuration needs attention as well.