Robert, here are several images I have found, showing the horn and/or where it is attached.
This is a shot of the overflow tank itself. Horn attaches to the front vertical strap.
This is my horn. I believe it is correct for a Ford Cab 13.
I thought I had a photo of the bracket itself, but can't find it yet.
Still, it doesn't matter because............I saved the best photo for last.
This should have all the detail you need. including how the bracket between horn & overflow tank looks. I got mine from ebay some months ago.
Hope this helps. Start your own resto thread, and you can post questions to your hearts content.
Any moderators able to help our new member to start a thread & possibly transfer the horn posts from here to there???