civil war boston and new york city uniform police buttons

Description

Lot of 2 civil war era police buttons.
The left button is a 23 mm Boston Police button with English script letters  B P.  A similar button can see in a lithograph of a Boston police officer in the 1865 A Chronological History of the Boston Watch.  The backmark is the Civil War era D Evans & Co Attleboro in ribbon
The right button is a 15 mm New York City police with an 1860s scovill mfg co waterbury backmark. This is the variant with the state seal possibly used by the metropolitan police as other New York state seal police types have the metropolitan police rmdc backmark
Condition.
The Boston police has a small push to the bottom of the letter P (see photos).  it is also worn and discolored from age.
The NYPD button has no pushes or dents but has some green corrosion on the back rim and some discoloration to the front (see photos)