Having dedicated much research to this topic, the earliest patent I can find on any type of buckle cover was held by Henry Pott, circa 1874. His cover, however, was an integral part of the buckle itself, and mainly served as a buckle loop, rather than a shield. The first true buckle cover patent that I could find was held by David Mosman, issued in 1879, and it more closely resembles the solid brass covers with the rigid ends that we also see attributed to the Civil War. The first true buckle cover that resembles these that we see with hearts was patented by Ralph Wooding in 1892. Prior to these dates, the only reference to buckle covers/protectors/shields was the use of a secondary leather strap that covered the face of the buckle. My research is always continuing as new information and leads come about, but so far, I have not found anything that definitively dates these to the Civil War era.
