Oh FFS, I give up at this point...
I would think a flimsy bright white, green and yellow plastic toy that every single kid in the entire world has would be blatantly obvious to anyone with a single brain cell. I personally think this prick was just being a prick.
I would think that putting this and a Nerf gun through an airport scanner would produce extremely different images. The only metal part of a Nerf is a spring or two and it weighs about a quarter of the lightest 9mm on the market... once again it's just a case of the world gone mad... or braindead!