I don't think they were Amfleets maybe heritage equipment.
You don't pay much attention to my posts, do you?
There were not two Amfleet-frame sleepers, there were four, and two more planned. Two of them were used initially on the Shenandoan, then were replaced by the second two. The third was set to replace them, but the Carter cuts had the meant they were never actually converted.
The first pair were indeed modified coach cars, as described... to an extent. The second pair were modified AmDinettes, with the sleeper modules taking up the non-table end, which it shared with a baggage-storage area. The third pair was to have consisted of a cafe counter, two booths, two sleeper modules, a small baggage storage area, and 24 coach seats, built into an SPV2000.
But what those sleepers consisted of is not accurately described. Amfleet's order options included options for 150 sleepers, not to mention 40 diners, and 40 cars designed to look like Amfleets intended to carry baggage, mail, and dormitory space.
The Amfleet sleepers were intended to be built with modules that mounted on the standard Amfleet coach seat tracking. The Amfleet fleet was intended, initially, to replace ALL east coast and much of the midwest and western fleet, with Superliners handling only the long distance western routes.
The sleeper modules designed included non-restroom single-person roomettes, two-person bathroomed bedrooms, and a "special" bedroom, a 10-3-1 with bathrooms. The Amfleet is a monocoque car, and thus could not handle the weight of baggage in large quantity- hence the reason that a specialized hybrid was envisioned for the baggage cars.
The Amfleet proved unsuitable to sleeper usage, and its high-speed trucks were deemed unsuitable for low speed use on bad trackage. Amtrak also found the success of the two-person Economy Bedroom so pointedly a reality that they realized building an 18-person sleeper was stupid. And the Amfleet did not have the upper space to handle upper births.
The Viewliner design was started soon after.