The Military would tend to wear a plain-faced buckle. The earlier the smaller the buckle would be, as the Military #1: brass was common but there were silver colored metals used as well. Pewter, Pennypinch, Nickel (white bronze) and Sliver. Then toward the midcentury the large and wider faces would be in favor. Military #3 , Military #4. Brass and Iron Oval and The Pewter Midshipmen would also be a choice here for the brass color or silver color buckles.