Tom , I have a question that popped up when I saw the subject gun in this post. Did Syracuse Arms use both color case hardening and bluing to finish their trigger plates. The couple of guns I have here, and other guns in the attached pictures seem to have had blued trigger plates.
It might be of some interest that all of the Baker boxlocks, which were related to Frank Hollenbeck, had blued trigger plates. I saw one Baker boxlock which was re color casehardened. The previously blued trigger plate warped badly. It must have been a type of metal that was different from the rest of the receiver which came out find.
