Footnotes in Fiction

I finally figured out which of the robbers had which gun. I am on what I hope is the final edit of the story. Set in 1889, it deals with early forensics, in this case rifling on bullets. I don’t usually put footnotes in my stories, but in this case I am tempted.

I have read books in which the history is pretty much made up by the author. I have read others that are researched to within an inch of its life. When I discover an odd fact and base a story on it, I want to make sure the reader knows I didn’t make it up to suit the plot. Soooo…..to footnote or not?