Mine is an 07, it was built (like all 07-08s) without the offending parts. I have "detents", I don't know what people are talking about.
The wedge and spring CLEARLY drop into place to keep the locking plunger from being able to move in the "LOCK" position, nothing more.

Also, one reason the key may more a bit easier, is that many of us (I sure do) put a few drops of light oil in the cavity before putting things back together. SOme assemblies have obvious lubrication, others dont, I always add a few drops of light oil in there before I wrap things up.