Joe

I have observations, but in all honesty I don't have any conclusions or provable conclusions.
Sheath 1 and 2 I think were made around the same time. Leather looks similar. Stitching, butterfly shape, keeper strap placement and width of belt loop all similar.
Sheath 4, the stitching is similar to 1 and 2. But the keeper strap is not in the middle. My "guess" it was not made during the same era as 1 and 2.
Sheath 5, IMO was made on a different machine. The stitches are longer, which is most evident on the butterfly. If I was to guess, I would say 4 and 5 were made about the same time due to keeper strap placement, but on different machines.
Also the leather on 4 and 5 looks similar. They both look different than 1 and 2, but that could be usage of the sheaths.