Makers Marks are usually placed in unseen areas but even if it was it still shows involvement.

There's way too much speculation these days about why something appears as it does and to assume just because the square and compass appears on this artifact, doesn't convict Freemasonry as supporting slavery. Freemasonry was born during the Christian crusades and understood the harsh life realities of indentured servitude and enslavement. People were born free or slaves and/or enslaved during their lifetime due to circumstances or conflict. Some were able to free themselves from bondage while others died. It was simply the way life was back then. That in no way makes Freemasonry guilty. Our enslavement today has become much more camouflaged.