Can You Identify These Libertarian Anti-Draft Protestors?

This fascinating photo is on the website of the Wisconsin Historical Society.

Here is the caption: "Students for a Libertarian Society march on State Street and burn their selective service registration cards in an anti-draft protest."

Although I was active in the UW-Madison SLS chapter at the time, and participated in one anti-draft march there, I don't remember the people in the photo.

I am not even sure that the picture is from 1981. It could have been a year or two earlier (when I was attending the University of Minnesota). Can anyone help me fill in the blanks?

By the way, anyone who has documents related to Students for Libertarian Society for any part of the country, I urge you to donate them to the Wisconsin Historical Society collection for that organization. Here is the inventory.