The shape is pretty close, although the scale is off. The one pictured is much too large for a normal Fett 'finder. However, for some shots in Alien, particularly the 'Space Jockey' scene, children were used in smaller suits, in order to make the Jockey appear larger than what it was.
With the 'finder being scaled, the helmet pictured appears too small even for a child's head.
Good eye, though!
