Colonial flat button ,or Gilt button... the Orange had more plate on them late 1700s early to mid. 1800s. Fell on of style around 1830s but use much longer.
Nice finds to help date sites.
Gary
decbra
Colonial is just the time period.
As for who`s button.... maybe a common man ,farmer or any one`s shirt of that time ....but most likly not military issue.
Gary