I did it and went for the blade spoiler. I love the blade as an homage to my first Camaro, a 1976 Black Type LT.
Anyway, the very long aluminum AM antenna stretches from end to end inside the factory vert spoiler. It's kind of a pain to get out. I haven't tried to re-install it in the new blade. I know someone on Camaro5 did. He just drilled out the new blade spoiler and stuffed it inside. I myself tried several aftermarket antennas, even with power boost, and they worked fine until you close the trunk. Then no AM at all. FM works fine. I'm just driving without AM, which I don't listen to anyway. Someday I'll try what the other guy did and stuff the antenna in the new blade. I think the antenna has to be above the trunk lid to get a signal.
I'm not sure the factory coupe spoiler is hollow like the blade spoiler, so you may not be able to stuff the vert am antenna in it. If you get the blade spoiler, buy it from the Chevy dealer who sells them on eBay. You'll save over $100. Good luck,