Cool catch, Richie!
Couldn't help but notice from the item description:
"With this working receiver and all the engineering specs., bandwidths, sensitivity, and selectivity shown in graphs in the manual, a search team can recreate the transmissions, much as mentioned in the link I listed, and with the receiver at the location of where the Itasca received the last transmission with this same receiver back in 1937, and perhaps it will steer them in the right direction!"
Yikes! Mystery solved!
LTM,
dp