Please assist in identifying a Leather Sword & scabbard carrying case I recently acquired. At least I assume that is what it is. The leather case is 42 inches long. I have included a link to photos of the case. It is inscribed in calligraphy script on the back of the flap, P. S. Elston, Aubudon, La. This inscription is on top of an earlier stamped inscription of which I can only make out the last word, Iowa. A Google search does not find an Aubudon Louisiana nor any reference to P. S. Elston. Inside the flap is hand written "C. S. Mst." and I can not make out the rest. Could this short for Confederate States Master (Sergeant)?

I do not know if this case is military related or possibly related to a Fraternal Organization. Could someone possibly date and identify this case for me.
Thanks in advance.
D. G. (Casey) Jones