This wardrobe prop was acquired many years ago from John Gorman the co creator of Alien War who in turn acquired it from a 20th Century Fox employee when he was sourcing original props for the Alien War experience held in Glasgow and London. Research shows it to be almost identical to a cap sold by the Prop Store of London which was sold as screen used. I am not making that claim as whilst I believe the Nostromo badge, scrambled eggs on the bill of the cap and in fact the cap itself are production and movie accurate I cannot personally match the cap to any screenshots I have studied. The interior foam lining of the cap has deteriorated over the years but you can still make out the lettering HDS No1 which I take to be a wardrobe mark meaning Harry Dean Stanton Number One. My assumption therefore is whilst I am entirely confident of the caps providence (having bought a number of Alien props from John Gorman over the years) and comparing it to the Prop Store of London's cap, this may not have been screen used but was undoubtedly created for the movie.