looks like a recast of a 3d printed TE made many years ago, its not accurate in terms of how it was made, its one solid piece made either by rotocast resin or fiberglass, the movie helmets were vacuumformed made from 4 separate parts, a face plate, top/cap and 2x ear pieces, also helmet should have real rubber brow and neck trim, this one is casted on helmet, not sure if it's 501st approved, TBH your better off with a more accurate vacuumformed helmet, way less work, no need to paint or add the missing details.
Mark (AP)