Would a Quaker have played a musical instrument at all at the time in question? According to Quakersong.org, "Traditionally (i.e. until the late 19th century) Quakers didn't believe in group singing or playing musical instruments." The Civil War occurred during the MID-19th century, of course. I suppose that if a mid-19th century Quaker would break tradition to enlist in the Union Army -- and many did, as InOBU attests -- then he could have broken tradition to play a bugle and rally others to fight.

Here's the contact info for the Solebury (Pennsylvania) Friends Meeting:

Solebury Friends Meeting
2680 N. Sugan Rd
New Hope, PA 18938-1070
(215) 862-5866‎
(215) 862-1419‎

For those not familiar with the area, it's in the southeastern part of the state, close to the Delaware River (the border between Pennsylvania and New Jersey), not very far upstream of where George Washington crossed the Delaware in 1776.

SharonA
(native of Bucks County and currently residing down the highway from Solebury!)