All sorts of people claim that a certain deviation was a factory car. A 292 with dual quads? I doubt it. It is possible that some one (maybe even a Ford dealer) put the dual quads on the car. Sounds like another fish story, like the guy that claimed his 55 came with the 55 sedan Fairlane trim or the guy that claimed the dual quads on a 56 was factory installed (dealer install only).
If there were 200 produced like this (292 with two 4 bbls), then it would be well known and documented. Ask a Tbird expert, not just some guy making a claim.
I would like to see the codes on the VIN plate
The only comment to pass onto the owner is that his claim is wrong
Midland Park, NJ
56 TBird, 54 Ford, 48 Ford, 64 Fairlane