As I understand it, yes. As I eyeball it, yes. I should be installing the hitch on Saturday, so I'll let you know and include some photos.
You can purchase a new facia without the notch to replace the one you have.
The hitch in Civic's photos is identical to the one I bought from Toyota except for the safety chain hookup. Civic's has holes for the safety chain drilled into the metal. The one I purchased has a metal loop welded to the bottom and one each side of the hitch. Also, the hitch is minus all those other parts items in Civic's photo. If your GX is like mine, you won't need all that other stuff except for the hitch and ball, but you can buy those at a generic parts store for much less than Lexus charges.
By the way, you can go to
www.Cabelas.com and order one of two objects that keep your hitch bar from rattling in the receiver....plus many other hitch items. Just type "hitch" in the search window.