Save Hollywood claims to have the actual bowler used in the Billyboy fight scene in Kubrick's A Clockwork Orange and that it was given to him by Malcolm McDowell. While the bowler in question is indeed signed by McDowell, the actor attends many fan conventions and will graciously sign anything you put in front of him. After all, that is what he's there for. And while I would like to give Save Hollywood the benefit of the doubt, students of ACO and bowler enthusiasts will note that the hat in his prop listing (here's the link: https://www.yourprops.com/Alex-s-Malcolm-McDowell-Bowler-Hat-original-movie-costume-A-Clockwork-Orange-Stanley-Kubrick-s-1971-YP57415.html) is not even close to what McDowell wore. Careful examination of the fight scene shows the hat falling off of McDowell's head in one of the shots where he is hit with a part of a window. In the first of the two shots I've included you can see the inside of the crown and the hint of the sweat band, which is white and padded and has a white drawstring at the top. In the second shot, you can see the hat falling past McDowell and the the full wide edge of the white sweatband. This type is known as a "hunting pad" for use in equestrian bowlers. Equestrian bowlers are extremely hard, so hard a person of moderate weight can stand on them without damage occuring. The last picture shows the bowler McDowell actually wore, which is owned by an English gentleman to whom Kubrick gave the hat right after production ended. This gentlemen, whom I know personally and who will remained unnamed, still owns this hat.
Conclusion: While I genuinely believe Save Hollywood is not purposely perpetrating a fraud, and that he genuinely believes he has the actual prop used in that scene, I can assure you he does not. Look at the comparative photos I've provided and decide for yourself.