ZL1 spoiler, if it has the factory ZL1 pegs, etc., will use 4 of the 7 holes you have in your trunklid. You will need to plug the 3 right in the gap under the 3rd brakelight, or fill and repaint the trunklid to make them disappear.
When I did mine on the 2010, I bought the entire ZL1 trunklid/spoiler when someone was modifying their ZL1, so I didn't have to fill anything. But I did have to deal with vinyl stripes to match the hood. With the Transformers cars, they used one-off satin black stripes, so I had to buy two sets of non-spoiler Transformers trunklid stripes to get the right length of ends of the stripe to match the part that ran under the spoiler on the decklid. PITA actually. But I have no extra holes to worry about.
I think it makes the coupes look a lot better. Here's ours when I did the spoiler install over 10 years ago.
With existing non-ZL1 spoiler holes, this is what you're up against.
Some people plug them and paint the top of the plugs to match body color to save the cost of filling holes, and repainting the decklid. Almost can't see them, but they're there.
