Revolutionary War British 3rd Guards Pewter Vest Button

Superb Revolutionary War period British 3rd Foot Guards button. Identical to Troiani , "Insignia of Independence " B3G.e. page 36. 17mm in diameter.  Excellent untouched condition with original iron shank in perfect condition as well. Dark goldish patina indicates an underwater find most likely. As part of the famed "Brigade of Guards" the Coldstreams had a superb battle record fighting at  Long Island, Brandywine, Monmouth, Camden, Guilford Court House and Yorktown to name a few.  Ex. Troiani Collection.