It is easier to just look for a period holster that the gun fits into instead of trying to determine exactly what holster was made of a 32 Model 1896. That period holster for small frame guns often had a flap closure designed as both police and civilian use, but some were open with a belt strap. Try to broaden your search to include any small frame revolver and look for the style of the day. Since S&W did not make holsters, you will probably never find one with "Model 1896" stamped on it, but a barrel length stamp was often used.
I have a couple flap holsters from that period or earlier as shown below that would most likely been one design used for this model. I would guess that the vast majority of 1896s were probably never in a holster, but rather a drawer or vest pocket.