Ronin, I know of an NOS Shelby Gt grill assembly for sale on the SAI group but it’s not cheap. Other option is like you said, basic black grill assembly from AM. Could mount your Pony emblem to it…So Shelby said "no way to replace" as that was made a long time ago. To GriffX's idea, they mentioned try to back off the bolts and re tighten in case stress or torque is causing it. I'll look at how it is mounted. Looks like it heats up, expands and gets worse. Then it tries to lay back down as it cools. Probably eventually crack.
I did find a basic black grill on AM site that would work I bet. I could get the AM black grill and put a cobra on it. Then I would have a very valuable "one off" and a cobra would to add 10-20 hp right off the bat... (lol)