Yes, you can just pull the whole smash. Before you do that, take a flashlight and look down into the throttle body. An easy way to confirm failure of the plenum gasket is if you see an oily residue on the floor of the intake. It should be relatively clean. If the gasket has failed, the oily residue will have formed from crankcase oils and fumes being pulled into the intake. A modest leak won't show much in the way of oil consumption, but it is a vacuum leak, and that coupled with even modest amounts of oil can cause issues with the whole electronics feedback system.
The gasket has been upgraded with a steel inner liner, but they can still fail, especially if torqued improperly, so do it right. Equal application of pressure is so vital, Hughes Engines sells a kit to more effectively apply equal clamping pressures. Beyond that is a much more pricey intake manifold replacement. Still, for every day driving, just do it right and it'll last a good long time.