To answer your spoiler question - yes.
As for the other one, it's not anything major, but it's not completely pointless either. If you've watched all the other clips at the ends of the other movies I don't see why you wouldn't wait for this one.
Ok, thanks. Will definately see first scene, but have to think about that second one.
I waited for IM3 scene and was disappointed. Didnt wait for Avengers shawarma scene and watched it on bluray. And didnt feel like I missed anything.