For your consideration, here is a 1973 Longview 50th Anniversary Brotherhood of the Brush Pinback Button, Washington.  It has a little wear on it and some tarnish on the back.  The button has a diameter of 2 1/4 inches.  Item pictured is the actual item up for sale and comes from a non-smoking household.  (347.315h-.4px2)
 

[Thanks for looking!]