DownNDirty, the base of spur is solid, app. three quarters of inch wide. It was found in good colonial area, lot's of colonial relics found area, I know that does not make it colonial. Thanks!
Looks like one of the stirrups in "Neumann and Kravic's Collector's Illustrated Encyclopedia of the American Revolution". This TNet thread from 2006 shows a page from that book showing Rev War era stirrups and one of them looks very similar to your stirrup.