The formal specifications certainly represented the conditions for conventional battleships.
However, there is reason to assume that there were also informal specifications that Sam Carp presented to potential contractors verbally - or subject to their secrecy
The secrecy when trying to order battleships in the USA was paranoid, and Sam Carp was the only person who knew the terms of the specification from the Soviet side! (perhaps, except for Brzezinski).
Since Corp was a personal confidant of Soviet Prime Minister Molotov, he received these specifications directly from him. He began negotiations with American firms in 1936 before the Brzezinski Commission arrived in the United States.
The Soviet Commission did not know the specifications and did not participate in their development or correction. The Commission only assessed the possibilities of their technical implementation.
Hybrids of battleships and aircraft carriers were not popular in the US Navy, and, as far as I know, were not worked out in the 30s. Only the Scout cruiser/aircraft carrier project is known. At the same time, two American companies presented battleship/aircraft carrier designs for the Soviets that contradict the official specification. It can be assumed that in a single case it was the personal initiative of a designer who was passionate about this idea - but there were at least two who made these proposals
It is significant how the Soviet Commission evaluated the first of that battleship/aircraft carrier project:
"In March 1937, an offer was received from the design firm Gielow Inc. corporation to develop the project according to the tasks previously reported by the Broker (Sam Carp - K.), which he received in Moscow.
The proposal was as follows:
1. In order to accommodate up to 60 aircraft on the battleship and use the upper deck for them, the main artillery, located in 3 forward 3-gun 16” turrets, was shifted to the starboard side (it is unknown how the designer will eliminate the roll).
2. The battleship does not have funnels, the discharge of flue gases is planned under water (without any explanation).
3. The standard displacement of the battleship is 35,000 tons, the speed is 30 knots.
4. High—pressure boilers - 85 atmospheres, range — 5000 miles, side armor — 14".
By checking the design material, it was found that the design material is very schematic.
Errors were found in the calculations, such as: the armor weight was indicated as 12,000 tons, whereas according to preliminary calculations, the armor should weigh at least 20,000 tons.
In the course of further negotiations with the company, it was established that it was not suitable for the implementation of the battleship project, as a result of which negotiations were terminated."
So, the battleship/aircraft carrier project was developed "according to the assignment reported by broker in Moscow"
The commission has questions about the discharge of gases, the roll of the ship, the estimated weight of the armor. But no attention is paid to a small detail - 60 aircraft on board, contrary to the formal specification
After that, a similar offer from Gibbs & Cox in august-november 1937 does not look bizarre, but a new link in this chain.