I thought it was a pull at first but there's an protrusion on the back that has a hole and there's rusted nails or rivets it's odd I'm a wood worker and I restore a lot of old furniture and it doesn't resemble an old pull.
Very exceptional Colonial rifle/musket Trigger Guard and in remarkable condition!!! (Rarely are these found completely intact, and more often than not, only shorter bits and pieces)
More it has provision for using pins to attach through holes in lugs. That should help in dating. Incised lines over bow could have been done by builder.
Guards usually reflect local school of building, ends easily custom shaped, but some like those with tulip finial at front could be imported.
A fowler or chiefs grade fusil just a couple possibilities. To long for yager,not screw holed for later n,w.trade gun. Not familiar penn. With squared ends and lacks a spur found on later styles, leaving guess still mid 1700s with earliest being 1600s. Some one knows its date use!.