Mine is gutted from the original owner. I do not have a Check engine light but I do know that a local dealer here dyno tested the shelf vs. no shelf and the shelf put out like an extra 2 horsepower or something.
So leave it be. I actually bought a complete airbox with a shelf to put in my sled. The other problem is the shelves are already prone to splitting open. Once you open it up to remove the shelf it is very prone and actually hard to keep closed. So even if you want to try and remove it for a butt dyno, you will cause yourself more problems in trying to keep it sealed.