I've got the umbrella hand-brake. It was a $350-$500 option with IM 15 years ago. It is in no way worth $500. I was hung up on "the tell" of a tunnel-mounted hand-brake - but at this point I don't care who knows it's a replica or what they think about it, and a tunnel-mounted brake is 10x more useful than the umbrella.
Do as you wish. Your mileage may vary.