It confirmed some speculation and provided more information.
Seven ultrasonic function blocks are clearly visible in the remote (tint, volume, on-off, etc.) and in the receiver, although there is an eighth in the receiver for the hard-off function. Only tubes (no transistors) are visible in the receiver, and it appears that dc motors are used. Can't decipher how the fine tuning works though.
There seem to be seven, not 14, ultrasonic tones used.
How then is the up/down function accomplished? Pulse/CW? Pulse/Pulse? (Either one with a simple f-to-V converter and threshold detector?)
In another email, Steve indicates that a transistor was not obvious in the parts list. Puzzle is still: what's the active device in the remote? There must be one there somewhere.
The drawing with relays and tubes showing is attached.