So I looked up the IAC replacement on YouTube for a 2.5 (I had a 2.4). You didn't need to pull the 4 bolts out of the throttle body. The two screws that mount this into that IAC "manifold" (the part you removed with 4 bolts, I'm just giving it a name) hold the IAC to it. If you just removed those two it'd come out in one piece, and the new one would have an o-ring where the IAC mounts to that manifold.
It's definitely misleading lol, but there are times where the IAC does have to be replaced. The gasket is hard to find because it isn't in demand, as you don't actually need to pull the square piece off to replace the more common failure point, which is the IAC valve.