Raimey, Please forgive my ignorance, but do you speak/read german? There is an article about the patented safety mechanism of my gun that is entirely in german.I have a copy but no translation. It references the patent date of 1891. I've been told it's all about the patent and not about the gun maker. Still it's something.
I will pull the gun out tomorrow and shoot some better pics of stamps and get an answer for you about the letters inside the heart stamp. Also a better profile of the gun. It is a field grade no doubt, but certainly well made and quite robust.