[Boatanchors] Dual crystal calibrator module

[Ian Wilson]

Trying to identify a plug-in module. It would be about 6" x 2" x 2" with a
(missing) U-shaped cover. Manufactured quality is high, light steel.
There is an octal plug on the base.

There is a pair of 6BA6's on top (possibly not the original tube type).
There are sockets for HC-6/U crystals (crystals not present). One of the
tubes is configured as a Pierce oscillator. The other has been partially
rewired.

Would like to know where this belongs, or what receivers from similar
(miniature tube) period had dual frequency crystal calibrators so I can
look at the schematic.

73, ian K3IMW