1970 am radio qustion

[rockyrivermark]

I have a original am radio that is not working.
I bought the truck last week and there isn't a wire harness in truck for it.
I wired it on the bench to test but wouldn't power up. at least no power to the light with a tester on it.
temp wired a speaker and got nothing but i'm reading that those old am radios take a special speaker.
question is:
1. I found a picture of the wire harness online (pic attached). Back of radio shows 12v, ground, and speaker. only one terminal for speaker. does the speaker ground to body and only use one wire?
2. In the pic of the harness, which again I don't have. yellow is 12v., black is ground for radio, green speaker positive?
thanks for any input or advise on what I can test.
thanks, Mark.