Is This An Alternator Wire

[Tifton81]

Help....I found this wire hanging and need help identifying it. As you can see it's a black wire that comes out of the wiring harness close to the alternator. The plug for the alternator seems to be missing a wire. I've tried to identify it but before I go and make a connection and fry something, I thought I would ask for your help.

 

[Tifton81]

Heres another picture.

 

[68Roadster]

Heres what the 81 wiring diagram shows.....

Brown and red going into the connector, hot red BAT wire and a black ground.