I'm not at all surprised. You were, after all, the one claiming some months ago that tracts of land in Greenbrier County were awarded for military service, weren't you?
Here's one article:http://tinyurl.com/9x8jbsu
I'm sure there are others. A Google search informs me of several notable exceptions, though, such as John Carter Littlepage, b 1752 in Virginia. Peterfield Jefferson, b 1735, cousin of President Thomas Jefferson, is arguably another, but such examples still seem somewhat rare, outside of specific regional custom. That alone should suggest caution and experience will teach you that such caution is entirely justified.
You may also find that under English Common Law your name was the one you were given at baptism. So, if the parish registry read, "Mary", then legally Mary it was, even if she was a "Mary Elizabelle" around the supper table.
What I'm seeing, though, is that the practice of giving children two or more names plus a surname flourished among German immigrants and spread with them down the Valley Road and beyond. By the mid-nineteenth, the practice was ubiquitous, but at least in my lines, and in the records I've seen, all the pioneers of this area seemed to follow English custom, when naming their children, until after the Revolutionary War.