I'm not sure, mostly because I haven't heard any concrete details on the Amero.
Last I heard, they're gearing up for a North American merger...but I haven't heard anything concrete (dates, etc.)
I know they still have to build that MASSIVE highway, which technically doesn't require the union to be consummated before it's built. It's just a really big superhighway (though it will be several football fields wide, with rail lines, customs offices, etc.)
Matthew