Thanks for bringing up my old post. Great memories on that one.
About all I can tell you is that this is a commemorative button from some early period, and it was unique enough to be listed in Albert's button book. I can't remember if the book said the reason it was produced, I'll check with Bedford Bob tomorrow and see if he can refresh my memory. I can say that I found a lot of 1820-1830s artifacts at this site, and there were zero modern items to be found there. The 1886 time frame you mentioned in your PM seems to be a bit later than what I would expect for this button.