There are six pointed Sheriff's Badges that look exactly like David Shields, but there are also five and seven pointed Sheriff's Badges, and there are also oval Sheriff's Badges.
So it is not accurate to say that Sheriff's Badges are in the shape of David Shields, but there is a common denominator- they both are meant to protect their carriers, and their carriers are meant to protect their people.
Photo courtesy of Mr. James Duffy, SAN DIEGO COUNTY SHERIFF'S MUSEUM,
6 point balled tip stamped nickel star badge made by California Stamp Company in San Diego. Known to be worn circa 1910, and it is the oldest known style.