This jacket has a weird fit. It's supposed to be belted, but looks to be the length of a Brad or a Kerala jacket. Especially so when they removed the belt and the belt loops altogether for the show.
EDIT: Correction. Under the new Belstaff brand what was know as Brad is now called Burgess.
Coincidentally, I own a Malenotti era Sammy Miller Jacket. Based on the fit, I am not convinced that it's a match. The Sammy Miller Jacket is a slightly boxier Trialmaster. The back length on my large (which matches up with the Mr. Porter measurements) is 30". Even if I were to size down to a small, the back length would still be 29.5" (according to Mr. Porter). For comparison, the back length on my large Brad is 25".
It does look like most of the styling cues match up. The only discrepancy that I noticed was that there is a patch of material directly under the top left pocket that doesn't appear to be in the Jack Bauer pictures. Granted the angles aren't great.
All of that said, I have a large Sammy Miller Jacket that I haven't worn in a year. I'm willing to listen to offers if anyone is interested in it.