While listening to the podcast "The Stuff Dreams are Made of" episode from January 14, 2021 "Displaying for Keeps" David Mandel discusses one of the most difficult props he owns in regards to creating a display... that prop? A Boba Fett jetpack.
He only mentions the Boba Fett "backpack" briefly starting around 47:10. Based on what he says, we can't be sure if he has an Original Trilogy jetpack or one from The Mandalorian... but if I had to place a bet it would be that he has one from the OT to pair with his PP2 Boba Fett helmet.
David Mandel also owns the Pre-Production #2 Boba Fett helmet as noted in this New York Times article.