[W. Knight]

Question, when whoever presented back then had a caller on and I think they used these for effect, my mind is misty about things like these. Did they ever hear the caller on through these or was it always through the earpiece and the telephone was just there for show?

Can't find any video of the actual phone-ins, but judging from this snippet in their CA (with the yellow handset), the former might be possible:
youtu.be