[Accelo]

Here are some pictures that may help.
The radios are easy enough to find.
Decent speakers can be purchased new as I did.
Show in the pictures below.
The brackets are a lot more difficult to come by.
When you wire the speaker be sure to get the black (-) on the correct terminal.
You can see the wood spacer that came with the new (reproduction) speaker.
This is so it will fit the bracket correctly. This same speaker was used in many other GM vehicles.
However, the brackets may be specific to the vehicle.
Rick