All the metal cased Arvin radios I've seen and worked on, have a floating B- line, with a capacitor from the B- to the chassis.
The cap will pass a small amount of AC voltage to the metal cabinet. It will probably trip a GFCI receptacle, as they are designed to trip at about 20ma leakage. That is dependent on the position of the line plug. Also, if the switch is on or off.
All the receptacles in my workshop are GFCI protected.
