Looking forward to the scan! From what I can see of it, this unit is an early version of Fisher's time division concept, but lacks the refinement of their later WX and MPX-65 (and other) units. It uses two single diodes for detection of the regenerated sub-carrier, as opposed to the dual ring detectors of their later units, but still functionally operates the same. Should be very interesting to get your impression of how well it performs!
Dave