itsyoung!!
Veteran
It was a fake. Remember it got smashed in Thor 3. I remember reading years ago how they just kinda three it in the first Thor movie as a cool little easter egg with no connections (sorta like Cap's shield in the first Iron Man), but once they got further along in the storyline, they had to retcon things in the earlier films.
even if it was fake, it would have a story to it.. hes seen it before (unless they are just blatantly ignoring hes ever seen it) and knows what it is. But in this movie he acts as if never seen it before (down to the design... hes literally asking the giant dwarf about the design and reason for the gauntlet)