1965 Valiant radio wiring harness question

So my 65 Valiant does not have a radio. However, the fuse box has a fuse in the radio slot and is live in the on and acc positions. Before I try to get under the dash and get my bifocals to focus, was the wiring harness to the radio installed in non radio cars. I've got a factory AM radio that was pulled from a car and stored all these years. Bench testing shows it works and sounds great.