1951 Zenith Porthole Question

[Ampico-kid]

I've been working on a 1951 Zenith Porthole combo set for some time now and have finally progressed to the point of reassembly. When I picked up the set the original 12" speaker was missing, but I have an EV dual cone replacement I was planning on using.

The AM/FM radio/phono amp is a "free standing" unit containing it's own amp, power supply, AM/FM Tuner, etc. The TV power supply chassis has it's own self contained amp dedicated to the TV. The potential problem...or question is this: with two independant amps, and a single speaker, how would both outputs be attached to it? Was the original speaker a dual voice coil unit? Or was there some sort of a switch somewhere? I don't see any provisions for external switching... unless it's missing?

Any information would be appreciated.
Thanks.
Bob.