Pictures are worth a thousand words. Now take the gun apart and look at the bottom of the barrel flats, the proof marks will tell the story, not whats on the barrel rib. Take pictures of the proof marks so they can be seen and people can tell you where the gun was made and about what time period.
Yep - pics of all the marks underneath on the flats and water table will aid greatly
The only thing besides this post that Google turns up is a town in Iowa of Panora. - Could this be the name of a business there that had the gun made for it 100 years or so ago?