Oldblue,
that sounds like quite a scoop you got at the swap meet.
First, I would not try it out on a battery without a fuse in line. I like to use a trickle battery charger for my testing.
Always make sure the volume control is turned to minimum when you start testing. If the speaker that you are testing with gets disconnected and the volume is turned up, it can be harmful to the radio. Any old speaker, preferably 8 ohm, will do.
I would suggest pulling the vibrator, which is inside, powering it up and check to see if all the tubes are lit and the off and on switch works.
The next step would be powering it up, with the vibrator installed and an antenna or hunk of wire inserted into the antenna socket. If you use a piece of wire, it should be insulated except for a short length that inserts into the center.
If you wish to, try these steps and let us know what happens.
Good luck!
