mounting factory style center speaker

[Firefighterkk]

I have a 69 c10 non ac truck that I ordered a radio setup off ebay. It has a factory style center speaker. Anyone have any insight in to how it mounts? does it hang off the dash pad stud? My truck did not have any speakers or a radio in it when I bought it, so I have nothing to go off of. Have tried to research it but have had no luck.

Here is the link for the radio I ended up with. Its a custom autosound.

http://www.ebay.com/itm/1967-1972-Ch...405666&vxp=mtr