Yes, we would love to see a photo or 2. You will have to have provenance or some proof this was actually worn by Elvis, or even worn in one of his movies at all.....still might be of interest even if worn by an extra or EP stand-in or EP double. Or it could have been made for Elvis to be worn in a movie, but it may be an "extra" shirt that he never actually wore. If it is a film studio costume, it should have a tiny and usually hand written cotton label sewn inside, or sometimes they wrote on the selvages with initials of the actor and the scene #. Of course these can be lost or removed over time.
Do you know the name of the movie? You can watch all of Elvis's movies to see if you can see the shirt in the film.
But without any proof, a reputable auction house will not want it.
If you can pinpoint a scene in a movie with Elvis wearing that same style shirt, and you have no proof, Ebay might be the way to go and sell it as "Elvis style" as worn in that specific film, etc. .
Bonham's Auction here in Hollywood might be of some help if you have provenance.