Iβm no expert, but from what I have learned here, they are from the early to mid 1800βs, someone correct me if Iβm wrong. I always like to find flat buttons. From what Iβm told, the buttons made of tombac are older as it was more in fashion in the mid to late 1700βs. Smokey the cat should be able to give you a better idea than me.
Sorry not the right pictures. Thanks grasshopper. Computer, Apple, pictures are saved in PHOTOS