If your talking about the pre 1908 upgrade sling set up with the magazine mounted rear sling mount and the front sling mount on the front barrel band then there are 3 types. The earliest type was canvas or leather and was sewn onto the sling loops, because you couldn't remove the sling without cutting it off few survive today outside of museums in Russia. The second type is leather with a hook on one end and a leather buckle similair to Austro-Hungarian
M1895 slings, it is also extremely rare. The third is a leather sling with a button loop on one end and a square buckle on the other, many of these survived in Finland
and can be found from time to time although not common. They are similar in design to the brown and green leather Mosin slings Finland used later on. Full disclosure: These pictures are from Vic Thomas's Mosinnagant.net site which is currently shut down.