Just my 2 cents...
Clearly these papers have been attached to these sheaths for a very long time. If this was an attempt to deceive about the age of these sheaths it would be a very good forgery indeed. Better, sharper photographs would beg helpful though, Ariel.
But if we do assume that the papers were in place for a very long time i don't see that someone even 50 years ago would bother to try to deceive anyone with dates just 100 years previous. What would be the point? Ariel took the time and effort to have these papers scientifically analyzed. I see no reason, therefore, to doubt the dating of these sheaths give the age of the paper. Even if the numbers themselves do not represent dates, the paper and ink has been proven to be 19th century, so i find little to doubt with this finding.
I also don't see why expert examination to determine whether or not the handle is rhino is a bad thing. Photographs can be deceptive, and if you are not too offended by this professional photographer's opinion Ariel, your photographs are just not clear enough to really determine anything for sure.
So personally i would welcome your expert's testimony from the Museum of Natural History.
Why would anyone
not welcome such evidence?