Stop in for a cup of coffee

This is the one. It also works the key buzzer. Many other places show they have the right part, but then you see it is different. Thanks Keith for the help!
NOS MOPAR 1971-3 B C & E BODY HORN RELAY ALL | eBay
I got a 73 parts dart out here. I'll see if it has what you need.. If so, it's yours. I'll check in the morning when I get to work.