Martin Smith was a maker of some renown, in Greenfield, Massachusetts. I have long believed that one of my local gunsmiths here, in Princeton, Illinois, had been apprenticed to Martin Smith. His name was Samuel D. Hinsdale. He arrived here from Greenfield, Massachusetts, in 1838. There is a Hinsdale rifle in the Library here on ALR.
Brass triggers seem to be a regional feature, more often seen in the northeast, especially New York. They are sometimes found on midwestern-made rifles, but generally on guns made by makers with northeastern roots.