1965 Valiant radio wiring harness question

I read a 1963 TSB on Valiants being delivered with radios installed, but the antenna kit was in the trunk. Radios could be switched between cars if needed and then the holes could be drilled and rhe antenna installed. I just found it strange to find a fuse in the radio circuit of a non radio car. I'll have to get a mirror out and investigate further under the dash.