Original production made, perhaps screen used pants belt. The leather belt design was custom made by "Willie's" in Los Angeles. The buckle is no longer made but was made by a well known buckle manufacturer.
"MyProps" on here has the exact same one: (copy and paste link)
http://www.yourprops.com/Arnold-Schwarzenegger-s-Screen-Used-Hero-original-screen-used-costumes-wardrobe-Terminator-2-Judgment-Day-1991-prop-52324.html
Screen used link for same exact belt (copy and paste link)
http://www.screenused.com/?sectionID=item-detail&subsectionID=index.cfm&item_id=9018
