66 Barracuda radio wiring

In the Service Manual there is a diagram showing a radio with reverb. The dark green wire from the radio shows connected to the speaker and the black seems to be going into the reverb. Then there seems to be a gray wire from the reverb to the other post on the speaker.

1) What if you have no reverb ? where does the black go ? Does it go to the other speaker post or just stay disconnected ?

2) Also I assume that ground is the chassis, so if the black wire does not go to the speaker then the speaker's second post should be grounded ?

Thanks for any help