The Cowboy Gnome is a limited edition decoration on Farmville.
It was originally released as a part of Southwestern Event.
It was re-released on the June 18, 2011 as part of the FarmVille Birthday Classics event. It was available for 1 day as part of the Wild West theme, on the 5th day.
It was re-released on the September 21, 2012 as part of the Pirates Event, available to purchase from the market for 12 cash with 1,200 experience gain.
Cowboy Gnome Market Info (September 2012)