Hairiness varies quite a bit from one individual to another and isn't always consistent during an individual's growth. Fine hairs are also easily obliterated by a slip of camera focus or lower resolution. It's also not necessarily preserved well on molts if they have been knocking around for a bit. Usually the more important things to compare are overall proportions, claw shape, carapace shape, eye placement/shape, and placement of prongs on the body. The photos here are a good example of hair variation, although for a different species within the same genus:
UC Berkely's images of Chlorodiella laevissima
UC Berkely's images of Chlorodiella laevissima