Has the later model rear seat armrests too, which, although not original, are nicer in my opinion.
The intake manifold could have been a Hi-Po 289 piece perhaps? Not sure what the app, but I've seen aluminum manifolds for Fords before.
Who knows, maybe it's some ultra-rare '60's factory stealth race program product that is one of only 3 made for the Shelby or Holman/Moody companies race efforts and was on the very first race Cobra or the winning engine in some other chassis of the '66 season. Hmm, maybe that's even the engine still bolted underneath it?
Or maybe a dealer item?
Paul